Note: Descriptions are shown in the official language in which they were submitted.
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HOT-FILLABLE AND RETORTABLE FLAT PANELED JAR
Field of the Invention
The present invention relates to wide mouth blow molded plastic containers,
and more particularly to such containers having opposed chordal vacuum flex
panels
which are particularly suited for hot-filling and/or retorting viscous
products.
Background of the Invention
A number of hot-fillable blow molded containers are disclosed having panels
that flex due to the hot-filling process. For example, U.S. Patents to: Brown
5,141,120; Brown 5,141,121; Krishnakumar 5,472,105; Prevot 5,392,937; and
Prevot
D 344,457 disclose hot-fillable bottles having panels providing the dual
function of
affording grippability and vacuum-accommodating flexure. U.S. Patent
5,887,739,
issued to Graham Packaging Company, L.P., and owned in common with the present
application, discloses a blow-molded wide-mouth container having a plurality
of
vacuum-flex panels spaced apart about its periphery. U.S. Patent D420,593,
also
owned by Graham, discloses a pinch-grip wide mouth container. While the
patented
Graham wide mouth containers afford the advantage of ready scoopability of
contents, the flex panels and dome structural intrusions into the container
may impede
thorough scoopability for certain types of viscous food products. Unlike
containers
having conventional peripheral flex panels that afford wrap-around labeling,
flex panel
grip containers of the type disclosed in the above patents have limited
labelable areas
due to the presence of the unlabelable grip areas between the front and rear
label
panels.
ln retort processing of containers filled with viscous products, such as
sauces,
the container is subjected to greater internal pressures and volumetric
changes than
occurs with hot-fill processing. This is due to the higher processing
temperatures,
and, therefore, the greater expansion of the contained products and associated
vapor.
In an attempt to provide a satisfactory retortable blow-molded plastic
container, U.S.
Patent 4,642,968 discloses a cylindrical wide-mouth container having a bottom
structure which bulges outwardly to accommodate internal forces developed
during
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retorting. See also U.S. Patents 5,217,737 and 5,234,126. U.S. Patent
5,908,128
discloses a narrow-neck bottle having a plurality of peripheral flex panels
that
accommodate internal forces due to pasteurization. The '128 patent does not
provide
ready contents scoopability because it has a narrow neck and is encumbered
with a
plurality of internal flex panel structural elements that interfere with
contents scooping.
There is, therefore, a need for a wide mouth container having a simple flex
panel
that presents a minimum of structure that can interfere with scooping of
contents yet
which is effective in absorbing vacuum without undesirable structural
problems. There
is also a need for such a container that provides a maximum amount of surface
area for
labelling. Furthermore, there is a need for a retortable wide mouth container
that can be
produced by economical extrusion blow-molding technology.
Summary of the Invention
With the foregoing in mind, the present invention seeks to provide novel hot
fillable plastic containers which have vacuum absorption panels that flex
during hot-
filling, capping and cooling; which are resistant to unwanted distortion; and
which have
a minimum of internal structure that could impede thorough contents scooping.
Another aspects of the present invention is to provide wide-mouth, blow-molded
jars having flat flex panels that present minimal interference with out-
scooping of contents
by a consumer and that maximize labelable areas.
A further aspect of the invention is to provide a wide-mouth, blow-molded jar
structure that can be used in either hot-fill processing or in retort
processing.
Yet another aspect of the invention is to provide a wide-mouth, blow-molded
retortable jar that can be produced by conventional extrusion blow-molding
technology.
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Brief Description of the Drawings
The foregoing and other aspects, features and advantages of the invention
should
become apparent from the following detailed description when taken in
conjunction with
the accompanying drawings, in which:
Fig. 1 is a side elevational view of one embodiment of a container according
to
the present invention, the opposite side elevational view being a mirror image
thereof;
Fig. 2 is a front elevational view of the container shown in Fig. 1;
Fig. 3 is a rear elevational view of the container shown in Fig. 1;
Fig. 4 is a top plan view of the container shown in Fig. 1;
Fig. 5 is a bottom plan view of the container shown in Fig. 1;
Fig. 6 is side elevational view of another embodiment of the present
invention;
Fig. 7 is a front elevational view of the container illustrated in Fig. 6;
Fig. 8 is a rear elevational view of the container illustrated in Fig. 6;
Fig. 9 is a transverse cross-sectional view taken on line 9-9 of Fig. 6;
Fig. 10 is a side elevational view of an extrusion blow-molded retortable
container,
embodying the present invention;
Fig. 11 is a bottom plan view of the container illustrated in Fig. 10;
Fig. 12 is an enlarged transverse cross-sectional view taken on line 12-12 of
Fig.
11;
Fig. 13 is a side elevational view of a modified embodiment of the container
of
Fig. 10; and
Fig. 14 is a rear elevational view of a further modified embodiment of the
container of Fig. 10.
Description of the Preferred Embodiments
As illustrated in Fig. 1, the present invention provides a blow molded, hot-
fillable
wide mouth jar J that has a body 10 with a pair of chordal vacuum flex panels
11 with
flat outer surfaces situation as shown in Figs. 2 and 3. The flex panels 11
are
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connected by an arcuate front label panel 13 and an arcuate rear label panel
15 of
smaller arcuate extent than the front panel 13, so that the panels 11 are
asymmetrically
disposed, both converging toward the rear of the jar J depicted to the right
in Fig. 1.
The flex panels 11 are planar, as manufactured, and flex in response to hot-
filling,
capping and cooling. Each flex panel is identical in construction to the
other.
As illustrated in Fig. 1, the flex panel 11 is vertically elongate and is
defined by
two opposing upper and lower U-shaped reinforcing rib structures, 19 and 20,
respectively. Each rib structure is identical to the other and is
characterized by a pair
of parallel vertical legs 19a which are connected together by an integral
peripheral
brow web 19b.
As illustrated in Fig. 3, the brow web 19b has a wall portion 19' that is
angulated with respect to the planar vacuum panel 11 and has a region of
maximum
intrusion extending centrally into the flex panel and end regions of minimum
intrusion
adjacent the intersections of the brow web 19b and the legs 19a. The region of
maximum intrusion of the brow web wall portion 19' intersects the flex panel
11 at an
included angle a of about 120 .
As depicted in Fig. 1, each brow web 19b has a portion, opposite the flex
panel, which extends peripherally of the jar inwardly adjacent conventional
peripheral
label bumpers. The ends of the rib structure legs 19a terminate in spaced
endwise
relation adjacent the transverse median M of the flex panel. The brow web and
legs
are continuously inwardly concave throughout their entire extents. The U-
shaped
reinforcing rib structures 19 cooperate to prevent ovalization of the jar
without
interfering with the desired movement of the planar flex panels 11 in the
course of
providing the vacuum absorption function during hot-fill processing. The legs
19a
provide anti-slip bights at the front and rear vertical edges of the flex
panels.
The upper portion of the jar J has a conventional dome shape 23 which
terminates in a wide mouth threaded finish 25. When made of PET and used in
hot-
fill applications, the base 27 of the jar preferably has radially extending
ribs (not
shown) such as customarily used by Graham in connection with other of its hot-
fill
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containers made of PET. An advantage of this jar structure is that in addition
to
providing the requisite vacuum absorption, it minimizes the amount of internal
structure that can impede thorough out-scooping of contents.
Another embodiment of the invention which provides enhanced labelability is
5 illustrated in Figs. 6 through 9. This embodiment is similar in most
respects to the
previously-described embodiment but has certain structural differences in the
flex
panel region that provide additional advantages. More specifically, as best
seen in the
transverse cross section of Fig. 9, the front label panel 113 merges smoothly
and
continuously into the front vertical margin of each flex panel 111 along an
arcuate
transition wall 130 having a relatively large radius of curvature, R.c, on the
order of at
least about 0.5 inch. The smooth radiused transition enables a continuous
label L, a
portion of which is shown in phantom in Fig.6, to be wrapped onto the front
label
panel 113 and into frontal vertical margins of each flex panel 111. Desirably,
a single,
inwardly-concave, vertical rib 150 is provided along the intersection of the
rear panel
115 and the rear of each flex panel 111. The rib 150 provides vertical
strength, and a
bight that facilitates anti-slip gripping.
This embodiment provides the advantages of the previously-discussed
embodiment, along with a larger label mounting area because the front label
can be
wrapped into the flex panel grip area, thereby enabling the front label to
occupy one-
half or more of the periphery of the jar body. lf desired, the rear panel may
be
labelled, or logos may be molded into the rectangular framed panel regions
115a,
115b, 115c.
Preferably, the planar flex panels of each disclosed embodiment taper
chordally
from front to rear at a dihedral angle 0 (Fig. 9) of from about 16 to about
32 , a
24 angle being shown in the illustrated embodiment. T'he chordal extent of
each flex
panel preferably corresponds to almost 30 percent of the transverse medial jar
body
circumference (ie. at least about one-half of the diameter of the container)
and should
be within a range of about 20 to about 40 percent. The height of each flex
panel is
about 50 percent greater than the chordal extent. The total labelable area of
the jar
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illustrated in Fig. 6 is about 20 in2. This is about 50 percent of the total
peripheral
surface of the body portion of the jar. Each flex panel is preferably smooth,
although
each may include a mottled surface, or may be embossed with decorations or
logos. The
containers illustrated in Figs. 1-9 have a volumetric capacity of 24.5 fluid
ounces,
and are illustrated at full scale.
Preferably, each container is manufactured of PET plastic from an injection-
molded prefozm. A wide-mouth container manufactured by this process is
disclosed
in Graham's U.S. Patent 5,887,739, referenced at page 1, the disclosure of
which
may be referred to for further details.
The disclosed container structures can be made by stretch blow-molding from
an injection molded preform of any of several well known plastic materials,
such
as PET, PEN, and the like. Such materials have proven particularly suitable
for applications involving hot-fill processing wherein contents are charged at
temperatures of greater than 190 F before the container is capped and allowed
to
cool to ambient temperatures.
A container structure disclosed in Figs. 10-14, which is similar to the con-
tainer of Figs. 1-5 but with certain modifications, has been found capable of
with-
standing the rigors of retort processing at temperatures up to 260 F under
super-
baric pressure conditions. Such structure is capable of being manufactured of
single
or multiple layer materials by economical extrusion blow-molding processes, as
well known in the art. For example, when an extruded parison having a six (6)
layer
wall structure of either virgin PP or HDPE, compatible regrind, adhesive,
EVOH,
adhesive, and virgin PP or HDPE is blow-molded into a 32 fluid ounce container
structure (illustrated at approximately twice full scale in Fig. 12) the
resulting
extrusion blow-molded container is produce-opaque; provides acceptable shelf-
life
for a contained viscous product, such as sauce, is economical to manufacture,
and is
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retortable. The term retortable, as used herein, is intended to mean that a
filled and
capped container is capable of being heated to temperatures up to 260 F at
pressures
up to 45 psi and cooled to ambient temperatures without undergoing distortion
that
would be commercially-unacceptable to the ultimate consumer.
According to the present invention, retortability is facilitated by an
improved
base construction which cooperates with the pair of flex panels to prevent the
base
from undergoing excessive outward deflection, ie. deflection below the
container
standing ring. To this end, as best seen in Fig. 10, a base 227 of the
illustrated cross-
sectional configuration has an annular peripheral standing ring 227a that
provides
upright support for the container when placed on a flat horizontal surface S.
The base
227 has an outer upwardly and radially-inwardly extending annular wall portion
227b
that tapers at an angle of 10 from the horizontal surface S. The wall portion
227b
merges with an inner upwardly and radially-inwardly extending wall portion
227c that
forms an angle of 45 with respect to a horizontal plane parallel to the
horizontal
plane of the support surface S. The outer and inner wall portions 227b and
227c are
connected by an inwardly concave wall portion having a radius of curvature R,.
The
inner wall portion 227c merges with an inwardly convex wall portion 227d
having a
radius of curvature RZ which is larger than radius R,. 'rhe convex wall
portion 227d
slants downwardly toward a central circular wall portion 227e coaxial with the
container central axis. The central circular wall portion 227e is located at
an elevation
H, lower than the elevation H, of the apogee 227f of the inner tapered wall
portion
227c. As seen in Fig. 11, the base 227 has a transverse mold-parting seam 227e
which is characteristic of an extrusion blow-molded parison.
Simulated retort tests were conducted on ajar of the configuration illustrated
in Figs. 10-12, which is like the jar of Figs. 1-6, but which has continuous
peripheral
outwardly concave reinforcing rings 230 and 231, respectively located above
and
below the upper and lower brows 219 and 220, respectively. The jar was
extrusion
blow-molded of a polypropylene multi-layer wall composition noted, sripra, and
had
the base configuration of Fig. 12 and dimensions set forth in Column A in
Table I.
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The jar was hot-filled with water at a temperatures of 150 F; was provided
with a 10
percent headspace; and was capped. To the capped jar, 1.7 fluid ounces of hot
water
at 150 F was added under pressure to simulate internal pressures experienced
during
retorting.
During the test, it was observed that the flex panels flexed outwardly while
the
base 227 acted like a diaphragm and deflected downwardly with its central wall
portion 227f remaining above the level of the standing ring surface S. It is
estimated
that the flex panels accommodated about 50 percent of'the combined flex panel
and
base accomodated volumetric expansion of the jar under simulated retort
conditions.
The combined volumetric expansion was about 80% of the total jar volumetric
expansion. The coaction of the base 227 with the pair of flex panels 211 that
flexed in
preference to the base, and the other disclosed structural features, enabled
the jar to
be retortable.
By way of example, and not by way of limitation, two 32 fluid ounce capacity
wide-mouth jars (A and B), both of the sidewall configuration illustrated in
Fig. 13,
having an overall height of 7 inches, a flex panel length of 3.5 inches and
width of 2.0
inches, a maximum outside body diameter of 3.7 inches, and base configurations
with
the dimensional relations (in inches) in Table I were tested satisfactorily
under the
simulated retort conditions noted above. Sample B had an outer annular wall
angle of
17 instead of 10 as in Sample A.
Table I
Parameter A B
D, 3.25 3.25
D, 2.38 2.38
D3 1.73 1.73
D4 0.39 0.39
H, 0.13 .195
H, 0.25 .315
R, 5.94 7.75
R, 6.35 6.35
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While these dimensional relations functioned well for a 32 ounce jar, when
scaling-up for larger capacity retortable jars, D3 should be made as large as
possible,
and H, should be larger.
lf desired, the extrusion blow-molded retortable jar shown in Fig. 10 may have
a flex panel frame structure such as shown in Fig 13. With such frame
structure, the
upper and lower U-shaped reinforcing ribs 319 and 320 have shorter legs 319a,
320a
separated from aligned vertically elongate ribs 319'.
Alternatively, instead of the series of vertically-spaced separately framed
panels illustrated at the rear of the retortable jar embodiment illustrated in
Figs. 6-8, a
jar may be provided with a single vertically-elongate arcuate rear panel 415,
as shown
in Fig. 14. The rear panel 415 is particularly suited for extrusion blow-
molded
retortable jars. The rear arcuate panel 415 can be molded with decorative
artwork
and logos.
ln view of the foregoing it should be apparent that the variouse embodiments
of the present invention overcome the limitations of known prior art
containers and
achieve the objectives set forth.
While several preferred embodiments have been described in detail, various
modifications, alterations and changes may be made without departing from the
spirit
and scope of the invention as defined in the appended claims.
