U.S. patent application number 12/433633 was filed with the patent office on 2010-04-08 for plastic container.
This patent application is currently assigned to Tropicana Products, Inc.. Invention is credited to Nelson S. Brent.
Application Number | 20100084359 12/433633 |
Document ID | / |
Family ID | 27753403 |
Filed Date | 2010-04-08 |
United States Patent
Application |
20100084359 |
Kind Code |
A1 |
Brent; Nelson S. |
April 8, 2010 |
Plastic Container
Abstract
A plastic container, especially suitable for long-term storage
of beverages that are hot filled into the containers, having in one
embodiment four relatively flat vacuum panels, having in another
embodiment a seven layer polymeric material with a nylon interior
layer, and having in another embodiment a combination of the other
embodiments.
Inventors: |
Brent; Nelson S.;
(Bradenton, FL) |
Correspondence
Address: |
BANNER & WITCOFF, LTD.;and ATTORNEYS FOR CLIENT NO. 006943
10 SOUTH WACKER DR., SUITE 3000
CHICAGO
IL
60606
US
|
Assignee: |
Tropicana Products, Inc.
Bradenton
FL
|
Family ID: |
27753403 |
Appl. No.: |
12/433633 |
Filed: |
April 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10083975 |
Feb 27, 2002 |
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12433633 |
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Current U.S.
Class: |
215/12.1 ;
215/382 |
Current CPC
Class: |
Y10T 428/1352 20150115;
Y10T 428/1383 20150115; B32B 27/08 20130101; B32B 27/30 20130101;
B32B 27/32 20130101; B65D 2501/0081 20130101; B32B 27/34 20130101;
B65D 1/0215 20130101 |
Class at
Publication: |
215/12.1 ;
215/382 |
International
Class: |
B65D 23/00 20060101
B65D023/00; B65D 90/02 20060101 B65D090/02 |
Claims
1. A plastic container suitable for hot filling, comprising: a bell
portion, a body portion and a base; wherein said bell portion
includes a neck for passage of a hot filled product therethrough
and a shoulder portion between said neck and said body portion;
said body portion having panel sections provided with respective
flat outer surfaces that are smooth and virtually flat, the panel
sections joining one another along respective smooth, rounded
corners and being operative to flex between an inwardly-bowed
configuration and a planar configuration in response to temperature
changes experienced by the container; and a first horizontal ridge
isolating the body portion from the bell portion and a second
horizontal ridge isolating the body portion from the base portion,
each panel section extending from the first horizontal ridge to the
second horizontal ridge, allowing the panel sections to have
sufficient flexibility to move between the planar configuration and
the inwardly-bowed configuration in response to temperature changes
experienced by the container, so that the panel sections act as
vacuum panels, wherein the smooth outer surfaces of the panel
sections and the smooth corners define a continuous outer surface
of the body portion that is smooth, uninterrupted, and devoid of
ribs, stress absorbing strips, raised areas, or recessed areas.
2. The plastic container of claim 1 further comprising a label
engaging said panel sections.
3. The plastic container of claim 2 wherein said label extends from
the bottom of said neck to said base, including said panel
sections.
4. The plastic container of claim 1 wherein said container is a
blow-molded polypropylene container.
5. The plastic container of claim 4, wherein said container is a
beverage container which contains a hot filled beverage.
6. The plastic container of claim 1 wherein said container has a
top load rating of at least 80 pounds at room temperature or
below.
7. The plastic container of claim 1 wherein two opposing side
panels have a mold line therein.
8. A multilayer plastic container comprising at least one wall
which defines an interior surface and an exterior surface of the
container, wherein said wall is formed of seven layers with a first
layer of polypropylene, a second layer of adhesive, a third layer
of ethylene-vinyl alcohol polymer, a fourth layer of adhesive, a
fifth layer of regrind, a sixth layer of adhesive, and a seventh
layer of polyamide and wherein said first layer of polypropylene
forms the exterior surface of the container and said seventh layer
of polyamide forms the interior surface of the container.
9. The plastic container of claim 8 wherein said container is a hot
fill plastic container.
10. The plastic container of claim 9 wherein said container is a
blow-molded container.
11. The plastic container of claim 8 wherein said fifth layer of
regrind forms about 70% or more of the thickness of said wall.
12. The plastic container of claim 11 wherein said first layer of
polypropylene forms approximately 20% of the thickness of said
wall.
13. The plastic container of claim 12 wherein said third and
seventh layers each form approximately 2% of the thickness of said
wall.
14. A multilayer plastic container formed of a polymeric material,
wherein said polymeric material comprises a layer of polypropylene,
a layer of ethylene-vinyl alcohol polymer adhered to said layer of
polypropylene, a layer of regrind adhered to said layer of
ethylene-vinyl alcohol polymer, and a layer of amorphous nylon
adhered to said layer of regrind, wherein said layer of amorphous
nylon forms the interior surface of the container.
15. The plastic container of claim 14 wherein said container is a
hot fill plastic container.
16. The plastic container of claim 14 wherein said layer of regrind
forms about 70% or more of the thickness of said polymeric
material.
17. The plastic container of claim 16 wherein said layer of
polypropylene forms approximately 20% of the thickness of said
polymeric material.
18. The plastic container of claim 17 wherein said layer of
ethylene-vinyl alcohol polymer and said layer of amorphous nylon
each form approximately 2% of the thickness of said polymeric
material.
19. A plastic container suitable for hot filling, comprising: a
bell portion; a body portion, generally rectangular in transverse
cross section and including four sidewalls joining one another
along respective corners, each of said sidewalls having a virtually
flat outer surface and being operative to flex between a bowed
configuration and a planar configuration in response to temperature
changes experienced by the container; a first horizontal, elevated
ridge disposed around the periphery of the container between the
body portion and the bell portion; a base; and a second horizontal,
elevated ridge disposed around the periphery of the container
between the body portion and the base, wherein the virtually flat
outer surface of each of said sidewalls extends from the first
elevated ridge to the second elevated ridge and between the
respective corners adjoining the sidewall; wherein said bell
portion includes a neck for passage of a hot filled food product
therethrough and a shoulder portion between said neck and said body
portion; and wherein said first elevated ridge isolates the four
sidewalls in the main body portion from the bell portion and the
second elevated ridge isolates the four sidewalls in the main body
portion from the base, so as to allow the sidewall to have
sufficient flexibility to move between the bowed and planar
configurations and so to act as vacuum panels.
20. A plastic container suitable for hot filling, comprising: a
bell portion having a neck for passage of a hot filled food product
therethrough and a shoulder portion located below the neck, the
shoulder portion having a cross-sectional area greater than a
cross-sectional area of the neck; a base portion forming a bottom
of the container and extending upwardly from the bottom; and a body
portion extending between the bell portion and the base portion,
the body portion having a polygonally shaped cross-section defined
by a plurality of panel sections joined to one another by a
plurality of smoothly rounded corners, each of said panel sections
having a smooth and virtually flat outer surface and being
operative to flex between an inwardly-bowed and a planar
configuration in response to temperature changes experienced by the
container, wherein when the panel sections are in the respective
planar configurations, the body portion has a cross-sectional area
that is substantially unchanged throughout the body portion,
wherein the cross-sectional area of the body portion is smaller
than the cross-sectional area of the shoulder portion at a juncture
between the body portion and the shoulder portion, to form a first
horizontal ridge at the juncture between the body portion and the
shoulder portion, the first horizontal ridge extending around the
periphery of the container, wherein the cross-sectional area of the
body portion is smaller than a cross-sectional area of the base
portion at a juncture between the body portion and the base
portion, to form a second horizontal ridge at the juncture between
the body portion and the base portion, the second horizontal ridge
extending around the periphery of the container, and wherein the
first horizontal ridge isolates the body portion from the bell
portion and the second horizontal ridge isolates the body portion
from the base portion, allowing the panel sections to have
sufficient flexibility to move between the planar configuration and
the bowed configuration in response to temperature changes
experienced by the container, so that the panel sections act as
vacuum panels, and wherein the smooth outer surfaces of the panel
sections and the smoothly rounded corners define a continuous outer
surface of the body portion that is smooth, uninterrupted, and
devoid of structural surface features, wherein the continuous outer
surface extends from the first horizontal ridge to the second
horizontal ridge.
21. The plastic container of claim 20 further comprising a label
engaging said panel sections.
22. The plastic container of claim 20 wherein the shoulder portion
of the bell portion comprises: an outwardly-curved upper portion
adjacent the neck; an inwardly-curved recessed area adjacent the
upper portion, having a cross-sectional area smaller than a
cross-sectional area of the upper portion; and an outwardly-curved
lower portion adjacent the recessed area and adjacent the first
horizontal ridge, having a cross sectional area greater than the
cross-sectional area of the recessed area.
23. The plastic container of claim 20 wherein said container is a
blow-molded polypropylene container.
24. The plastic container of claim 23, wherein said container is a
beverage container which contains a hot filled beverage.
25. The plastic container of claim 20 wherein said container has a
top load rating of at least 80 pounds at room temperature or
below.
26. The plastic container of claim 20 wherein two opposing side
panels have a mold line therein.
27. The plastic container of claim 20 wherein said container is
formed of a polymeric material, said polymeric material having a
layer of polypropylene, a layer of ethylene-vinyl alcohol polymer
adhered to said layer of polypropylene, a layer of regrind adhered
to said layer of ethylene-vinyl alcohol polymer, and a layer of
polyamide adhered to said layer of regrind, and wherein said layer
of polypropylene forms an exterior surface of the container and
said layer of polyamide forms an interior surface of the
container.
28. The plastic container of claim 27, wherein the polyamide layer
comprises amorphous nylon.
29. The plastic container of claim 27 wherein said layer of regrind
forms about 70% or more of the thickness of said polymeric
material.
30. The plastic container of claim 27 wherein said layer of
polypropylene forms approximately 20% of the thickness of said
polymeric material.
31. The plastic container of claim 27 wherein said layer of
ethylene-vinyl alcohol polymer and said layer of polyamide each
form approximately 2% of the thickness of said polymeric
material.
32. The plastic container of claim 1, wherein said container is
formed of a polymeric material, said polymeric material having a
layer of polypropylene, a layer of ethylene-vinyl alcohol polymer
adhered to said layer of polypropylene, a layer of regrind adhered
to said layer of ethylene-vinyl alcohol polymer, and a layer of
polyamide adhered to said layer of regrind, and wherein said layer
of polypropylene forms an exterior surface of the container and
said layer of polyamide forms an interior surface of the
container.
33. The plastic container of claim 1, wherein when the panel
sections are in the respective planar configurations, the body
portion has a cross-sectional area that is substantially unchanged
throughout the body portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/083,975, filed Feb. 27, 2002, which
application is incorporated by reference herein in its
entirety.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention is directed to plastic containers.
More specifically the present invention relates to blow molded
shaped plastic containers, particularly beverage containers. A
first aspect of the present invention is directed to the panel
design for hot fillable plastic containers, such as those for hot
fill beverages. More specifically, this first aspect of the present
invention is directed to a panel design for hot fillable plastic
containers having flat vacuum side panels. A second aspect of the
present invention is directed to multi-layer plastic containers.
More specifically, this aspect of the present invention is directed
to plastic containers having a seven layer polymer structure. A
third aspect of the present invention is directed to plastic
containers having the panel design of the first aspect and the
seven layer structure of the second aspect of the present
invention.
BACKGROUND OF THE INVENTION
[0003] Hot filled containers are designed for packaging of liquids
which must be placed in the container while hot to provide for
adequate sterilization. During filling, the container is subjected
to elevated temperatures of approximately 180.degree. to
185.degree. F. (the product temperature) and positive internal
pressures of approximately 2 to 5 psi (the filling line pressure).
The container is then capped, and as the product cools, a negative
internal pressure is formed in the sealed container. The hot fill;
however, can cause distortion and shrinkage of the container. It is
desired that the volume metric shrinkage be limited to no greater
than 1%.
[0004] Many different types of containers have been created to
receive a hot-fill product and meet the objectives of a minimum
amount of thermal shrinkage and distortion. However, prior efforts
to produce bottles for handling hot filling and to meet the above
objections have necessarily included panels having indents,
detents, protruding surfaces and/or recessed surfaces functioning
as so-called vacuum panels for container stress relief.
[0005] For example, U.S. Pat. No. 4,863,046 (Collette et al.)
discloses a blow molded container for receiving a hot fill product.
The container in the '046 patent, however, does not have flat side
panels but instead has a series of indents or recessed portions and
ribs in the side panels in order to minimize shrinkage and increase
longitudinal stiffness of the panel section.
[0006] Another patent disclosing a plastic container with vacuum
panels is U.S. Pat. No. 5,704,503 (Krishnakumar). The container in
the '503 patent also does not have flat vacuum panels, but instead
requires longitude post ribs flanked by walls, in between recessed
vacuum panels. Hoop ribs are also provided around the panel.
[0007] U.S. Pat. No. 4,877,141 (Hayashi et al.) shows another type
of vacuum panels. The '141 patent also does not have flat panels,
but rather the panels have stress absorbing strips to prevent
deformation of the container. Each panel is also surrounded by
outer sheaths.
[0008] Accordingly, these prior containers taught the need to have
specially designed structures to accommodate volume changes upon
cooling of hot filled products. These containers did not have flat
vacuum panels.
[0009] Therefore, one object of an embodiment of the present
invention is to provide a flat vacuum panel structure, without the
need for any such ribs or stress absorbing strips. This provides
smooth sides for ease of label application and cleanness of
appearance, while still maintaining a sufficient top load rating.
The smooth sides also provide an appealing feel for the consumer,
especially in the label area which does not suffer from the
wrinkled feel of labels on prior containers.
[0010] Another aspect of plastic containers relates to the plastic
polymer used to mold the container. Frequently, a multilayer
polymer composition is used to provide strength and other benefits
to the container.
[0011] For example, U.S. Pat. No. 4,182,457 (Yamada) discloses a
multi-layer container and several embodiments thereof, including
some with seven layers. Some are mentioned at columns 9 and 28
therein. These structures, however, have a polyolefin as the
innermost layer. Polyolefins have been found to rapidly strip the
limonene out of fruit or citrus juices. This adversely affects the
taste of the juice as limonene and other important flavor and color
components contribute to desirable tangy flavors and color of the
juices.
[0012] U.S. Pat. No. 4,990,382 (Weissenstein et al.) discloses
laminated blow molded containers which are said to provide a glass
like appearance. The '382 patent also discloses some containers
with seven layer structures. In these containers, the interior
layer is a polypropylene followed by a layer of adhesive, a barrier
layer, another layer of adhesive, a relatively thick layer formed
of regrind scrap containers, a third layer of adhesive and an
outside gloss coat layer formed from plastic materials including
ethylenelvinyl alcohol copolymer (EVOH) and nylon and mixtures
thereof. Since this container has polypropylene, a polyolefin, as
the inner most layer, the container will quickly strip the limonene
and other important flavor and color components out of fruit juice
therein and adversely affect the taste and color of the juice.
[0013] U.S. Reissue Pat. No. Re 34,546 (Deyrup) is directed to the
use of high density linear polyethylene for containers and also
generally discloses the use of seven layer structures for
containers. Deyrup '546 recites for example a seven layer structure
including polyethylene, adhesive, EVOH, adhesive, polyethylene,
adhesive and polyamides or nylons. While an amorphous
polycarboxlamide is used as an inner layer in some of the
structures of this patent, neither a layer of polypropylene nor a
layer of regrind is used.
[0014] Therefore, an object of the present invention is to provide
a plastic container having a specific seven layer structure which
is suitable for storage of beverages of juices, dairy products and
combinations thereof and which will not adversely affect the taste
and color of the beverages therein.
[0015] Still another object of the present invention is to provide
a plastic container having a flat vacuum panel structure and a
specific seven layer structure which is suitable for storage of
beverages of juices, dairy products and combinations thereof.
SUMMARY OF THE INVENTION
[0016] The present invention is directed to plastic containers
including those formed by blow molding, which are especially
suitable for long-term storage of beverages that are hot filled
into the containers.
[0017] In a first embodiment of the present invention, the
container has a rectangular cross-section body portion with four
panels wherein each of the four panels is relatively flat, but
flexible. These panels function as vacuum panels which buckle
slightly inwardly in response to cooling of the hot filled liquid.
The panels can move from a planar configuration and a bowed
configuration in response to filling with hot product and cooling
after filling. By having virtually flat panels, label application
to the container is simplified while providing a smooth,
aesthetically pleasing look and feel.
[0018] In a second embodiment of the present invention, the
container has walls formed of a polymeric material having a seven
layer structure of polypropylene, adhesive, EVOH, adhesive,
regrind, adhesive, and amorphous nylon. Preferably, the
polypropylene forms the outside of the container wall while the
amorphous nylon forms the innermost layer which contacts the
contents of the container. The amorphous nylon layer prevents the
beverages from losing their color and taste, due to either scalping
of key favor and color components out of the juice and into the
plastic and/or imparting from the plastic off note plastic flavors
into the juice. The other layers provide strength and a barrier
layer for contaminants.
[0019] In a third embodiment of the present invention, the
container has the flat panel walls of the first embodiment and is
formed as a polymeric material having the seven layer structure of
the second embodiment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a beverage container of a
first embodiment of the present invention.
[0021] FIG. 2 is an elevational view of the container of FIG.
1.
[0022] FIG. 3 is a top plan view of the container of FIG. 1.
[0023] FIG. 4 is a bottom plan view of the container of FIG. 1.
[0024] FIG. 5 is a perspective view of another example of a
container of the first embodiment of the present invention.
[0025] FIG. 6 is an elevational view of the container of FIG.
5.
[0026] FIG. 7 is a cross-sectional view of the seven layers of the
polymeric material of a container of a second embodiment of the
present invention.
DETAILED DESCRIPTION
[0027] FIGS. 1-4 show a first embodiment of the present invention.
This embodiment is directed to a plastic container 10, preferably a
beverage bottle, for hot fill liquids. The bottle includes an open
mouth 12 to receive hot fillable liquids, a bell (or upper) area or
portion 13, and a body (or lower) area or portion 15.
[0028] Concerning the bell area 13, surrounding the mouth 12 is a
neck 14 to receive a cap [not shown]. Preferably, the neck 14 has
threads for screwing on the cap. Below the neck is a shoulder
section 16 which increases generally in width from the neck to a
maximum point, lower on the container. The width then decreases to
a recessed area 18. Then, below the recessed area 18 is a first
elevated ridge 20. This bell area helps to provide an acceptable
top load rating for the container. The top load rating relates to
the ability of the container to have other items, particularly
other containers, stacked thereon. In this embodiment, a top load
rating of at least 80 pounds has been achieved. The bell area 13 is
able to provide sufficient strength so that it is not necessary for
the body portion 15 to provide a means for supporting a top load
weight which could include indents, detents, protruding surfaces
and/or recessed surfaces.
[0029] The body portion 15 is generally defined as follows. The
body portion 15 includes below the first elevated ridge 20 a
rectangular (longitudinally) lower body portion or panel section
22. Below the panel section 22 is a second elevated ridge 24 and a
base 26. As shown, the elevated ridges 20 and 24 have a greater
width (in transverse bottle cross section) than the panel section
22. Ridges 20 and 24 act to isolate the panel section and allow the
panel section to act as vacuum panels. These ridges also act as
bumpers for the bottles to keep the bottles flush to one another on
a conveyor belt during filling and/or capping and to keep them
moving along the conveyor belt. The ridges could also operate as
protection for a label located only on the side panels. Base 26
preferably includes a recessed closed bottom 28 as shown in FIG. 4
which moves inwardly to cooperate with the panel section 22 in
order to reduce the negative pressure during product cooling.
[0030] Preferably, the panel section 22 has a transverse
cross-sectional shape which is square but is not limited to this
shape. More preferably, the panel section has four flat side panels
which are rectangular. Typically, the side panels are substantially
identical in size, shape, thickness and composition. In a further
embodiment, the mold line (not shown) for the container is located
on two opposing side panels, as opposed to in the corners. In this
embodiment, these opposing side panels may be slightly thicker than
the other side panels.
[0031] Each side panel 30 is not only flat but flexible and has no
ribs, stress absorbing strips, recessed areas, or other similar
obstructions to panel bowing. Each of the side panels preferably
has smooth corners 34 between the two panels. A label can then be
smoothly and easily applied to the bottle. For example. a label 36
could extend from the top shoulder 16 to base 26. The present
invention, however, is not limited to the size or length of the
label.
[0032] While FIGS. 1-4 show the side panels having a long
longitudinal length, the panels can be of any length as for example
shown in FIGS. 5-6. In these figures, side panel 38 has a much
shorter height. Otherwise, the plastic container of FIGS. 5-6 is
essentially the same as the container shown in FIGS. 1-4.
[0033] The second embodiment of the present invention is directed
to a plastic container formed of a polymeric material and having a
seven layer structure. FIG. 7 is a cross-sectional view of the
seven layers in the plastic polymeric material of the walls of the
container. In this embodiment, the plastic polymeric material has
four structural layers and three adhesive layers.
[0034] As shown in FIG. 7, the exterior surface 102 of the
container of this embodiment is made of polypropylene, such as a
virgin polypropylene. The mid-outer layer 104 is an adhesive. The
mid-interior layer 106 is ethylene-vinyl alcohol polymer (EVOH).
The next layer 108 is another layer of adhesive. The next layer 110
is a re-grind layer. It is an interior, sandwiched layer. This is a
"scrap" of the seven layer co-extrusion which has been collected
and ground into polymer. Preferably the bulk of the co-extrusion is
the re-grind material, making up to approximately 70 percent of the
total thickness of the extrusion. The next layer is another
adhesive layer 112. These layers act as a barrier to keep
contaminants from the beverage and to give strength to the
container. As a result, the beverage within the container will have
a longer shelf life than other containers with such a combination
of layers. The contact or innermost layer 114 is a polyamide, such
as an amorphous nylon. It is 'the amorphous nylon layer which
contacts the contents of the container, such as a beverage within
the container. The nylon layer does not strip the limonene and
other important flavor and color components out of the beverage. As
a result, a fruit or citrus containing beverage will maintain its
tangy flavor and color longer and will not have a plastic
taste.
[0035] The following is an example of a plastic container having a
seven layer construction in accordance with this embodiment of the
present invention. Preferably, for a 12-ounce container such as
shown in FIG. 1, the weight of the bare bottle is 27 grams.
Materials used included a polypropylene (Marlex') manufactured by
Phillips, manufacturer No. RGN-020; an EVOH (Soarnol.RTM.) from
Soarus, manufacturer No. DCF3203F; and a nylon from Dupont
(Selar.RTM.), manufacturer No. PA3426. An adhesive from Dupont
(Bynel.RTM.), manufacturer No. CXA 50E571, was used for each of the
adhesive layers.
[0036] These materials were used in a polymeric composition having
the composition shown in Table 1 to produce a plastic beverage
container in accordance with the present invention.
TABLE-US-00001 TABLE 1 Target % of Layer Material Thickness (in)
Thickness Outer Virgin Polypropylene 0.006 20 Mid-outer Adhesive
0.0004 1.3 Mid-inner EVOH 0.0006 (minimum) 2 Mid-inner 1 Adhesive
0.0004 1.3 Inner Regrind 0.0216 72 Lower-inner Adhesive 0.0004 1.3
Contact Amorphous Nylon 0.0006 (minimum) 2
[0037] When being used to manufacture a container, typically the
polymeric material of this embodiment initially is in the form of a
parison which is extruded into a preform and blow molded into the
desired shape. It is contemplated that this will be done in a
conventional manner which is well known to those skilled in the
art. The present invention is not limited to a method of extrusion
or blow molding.
[0038] In a third embodiment of the present invention, a beverage
container of the first embodiment, such as that shown in FIGS. 1-6
and described above, is formed of a polymeric material having a
seven layer structure of the second embodiment, such as that shown
in FIG. 7 and described above. This combination is especially
suitable for hot filled beverages, particularly those which are
susceptible to development of off flavors when stored for long time
periods such as for about six months or more in polymeric
containers. The combination is also useful for containers for
beverages containing 10 weight percent or more of fruit or citrus
juice. Further, the combination is useful for beverages containing
fruit or citrus juice and dairy products, such as for example a
smoothie beverage with yogurt and fruit juice. In a preferred
embodiment, the smoothie beverage includes yogurt, approximately 50
weight percent of fruit juice and other additives.
[0039] It will be understood that the embodiments of the present
invention which have been described are illustrative of some of the
applications of the principles of the present present invention.
Numerous modifications may be made by those skilled in the art
without departing from the true spirit and scope of the
invention.
* * * * *