U.S. patent application number 13/615555 was filed with the patent office on 2013-01-03 for multi-functional base for a plastic, wide-mouth, blow-molded container.
This patent application is currently assigned to Graham Packaging Company, L.P.. Invention is credited to Richard K. Ogg, John W. Tobias, GREG TRUDE.
Application Number | 20130000259 13/615555 |
Document ID | / |
Family ID | 46301344 |
Filed Date | 2013-01-03 |
United States Patent
Application |
20130000259 |
Kind Code |
A1 |
TRUDE; GREG ; et
al. |
January 3, 2013 |
MULTI-FUNCTIONAL BASE FOR A PLASTIC, WIDE-MOUTH, BLOW-MOLDED
CONTAINER
Abstract
A container can have a body with an integrally formed base
attached to the body. The base includes a concave annular wall
extending from the container sidewall to a standing surface, and an
inner wall extending from the standing surface to a substantially
flat inner annular wall. The inner annular wall is recessed in the
base and is substantially perpendicular to the container sidewall.
The inner annular wall includes a centrally located dimple. The
dimple includes a plurality of spaced apart and radially extending
indented ribs. One or more of the ribs extend radially into a brace
that tapers to meet the inner annular wall.
Inventors: |
TRUDE; GREG; (Seven Valleys,
PA) ; Tobias; John W.; (Spartanburg, SC) ;
Ogg; Richard K.; (Littlestown, PA) |
Assignee: |
Graham Packaging Company,
L.P.
York
PA
|
Family ID: |
46301344 |
Appl. No.: |
13/615555 |
Filed: |
September 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12250856 |
Oct 14, 2008 |
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13615555 |
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10851083 |
May 24, 2004 |
7543713 |
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12250856 |
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10444616 |
May 23, 2003 |
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10851083 |
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Current U.S.
Class: |
53/471 |
Current CPC
Class: |
B29D 22/003 20130101;
B65B 3/022 20130101; B65B 61/24 20130101; B65B 7/28 20130101; B65B
63/08 20130101; B65D 1/0276 20130101; B29C 49/4273 20130101; B65D
1/0284 20130101; B29C 49/4252 20130101; B29L 2031/716 20130101;
B65D 79/005 20130101; B65D 21/0231 20130101; B29L 2022/00 20130101;
B29C 49/70 20130101 |
Class at
Publication: |
53/471 |
International
Class: |
B65B 7/28 20060101
B65B007/28 |
Claims
1-21. (canceled)
22. A method of processing a plastic container, comprising: (a)
providing a plastic container having an upper portion including a
finish, a sidewall, a lower portion including a base defining a
standing surface, and a substantially transversely-oriented
pressure panel located in the base, the pressure panel having a
truncated cone portion located at a central longitudinal axis of
the container, the truncated cone portion being constructed and
operative in the pressure panel such that a base portion of the
truncated cone portion is always below a top portion of the
truncated cone portion; (b) introducing heated liquid contents into
the plastic container with the pressure panel located in an
inwardly-inclined position entirely between the standing surface
and the upper portion; (c) capping the plastic container; and after
said step (c), (d) moving the pressure panel to an
outwardly-inclined position entirely between the standing surface
and the upper portion, wherein the truncated cone portion
substantially maintains a constant shape for said step (d).
23. The method of claim 22, further comprising the step of blow
molding the plastic container with the pressure panel in the
inwardly-inclined position.
24. The method of claim 22, further comprising the step of cooling
the plastic container and liquid contents after the step (d), said
cooling causing the pressure panel to move inwardly, wherein the
truncated cone portion substantially maintains the constant shape
for said moving inwardly.
25. The method of claim 22, wherein the step (d) occurs as a result
of increasing internal pressure within the plastic container.
26. The method of claim 22, wherein the truncated cone portion is
operative to prevent inversion of the pressure panel and includes
ribs radially extending therefrom, each said rib linearly tapering
in plan view at a substantially constant rate over substantially
its entire length.
27. The method of claim 22, wherein said step (d) includes moving
the pressure panel outwardly to the outwardly-inclined
position.
28. The method of claim 22, wherein said step (d) includes moving
the pressure panel from the inwardly-inclined position to the
outwardly-inclined position.
29. The method of claim 22, wherein the pressure panel includes a
wall, the wall being between a hinge and the base portion of the
truncated cone portion, the wall being circumscribed by a hinge and
circumscribing the base portion of the truncated cone portion.
30. The method of claim 29, wherein the wall is substantially
flat.
31. A method of processing a plastic container, comprising:
providing a blow molded plastic container having an upper portion
including a finish, a sidewall, a lower portion including a base
defining a standing surface, and a substantially
transversely-oriented pressure panel located in the base, the
pressure panel including a frustum-shaped portion at a central
longitudinal axis of the container, the pressure panel being blow
molded in a first inwardly-inclined position entirely between the
standing surface and the upper portion; introducing heated liquid
contents into the plastic container having the pressure panel
initially positioned in the first inwardly-inclined position;
capping the plastic container; flexing the pressure panel
downwardly to an outwardly-inclined position entirely between the
standing surface and the upper portion when the container is
filled, capped, and subjected to an increase in pressure inside the
container; cooling the plastic container and liquid contents; and
after said cooling, moving the pressure panel from the outwardly
inclined position to a second inwardly-inclined position entirely
between the standing surface and the upper portion to relieve
vacuum when the contents of the filled and capped container are
cooled, wherein said moving the pressure panel occurs as a result
of an internal vacuum formed within the plastic container.
32. The method of claim 31, wherein the first inwardly-inclined
position is different from the second inwardly-inclined
position.
33. The method of claim 31, wherein the frustum-shaped portion is
operative as an anti-inversion portion to prevent complete
inversion of the pressure panel, and wherein, for each of said
flexing and said moving, the frustum-shaped portion maintains
substantially a constant shape.
34. The method of claim 31, wherein the frustum-shaped portion is
in the form of a truncated cone.
35. The method of claim 34, wherein the truncated cone includes a
plurality of ribs formed therein, each of the ribs originating from
a base of the truncated cone and running toward a top portion of
the truncated cone.
36. A method of processing a plastic container, comprising: (a)
providing a plastic container having an upper portion including a
finish, a sidewall, a lower portion including a base defining a
standing surface, and a substantially transversely-oriented
pressure panel located in the base, and an anti-inverting central
portion surrounded by the pressure panel and opening downwardly in
the base, the anti-inverting central portion being frustum shaped;
(b) introducing heated liquid contents into the plastic container
having the pressure panel; (c) capping the plastic container; (d)
cooling the plastic container and liquid contents; and (e) prior to
said cooling, moving the pressure panel between an
outwardly-inclined position entirely between the standing surface
and the upper portion and an inwardly-inclined position entirely
between the standing surface and the upper portion, the
anti-inverting central portion traveling up and down with the
surrounding pressure panel while remaining in the downwardly-open
position and maintaining a substantially constant shape, wherein
said moving the pressure panel occurs as a result of an internal
vacuum formed within the plastic container.
37. The method of claim 36, further comprising the step of blow
molding the plastic container with the pressure panel in the
inwardly-inclined position.
38. The method of claim 36, wherein the outwardly-inclined position
and the inwardly-inclined position are maximum desired limits
within which the pressure panel can move.
39. The method of claim 36, wherein the pressure panel further
includes a plurality of tapering ribs adjacent the anti-inverting
portion.
40. The method of claim 36, wherein the anti-inverting central
portion is in the shape of a truncated cone.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a division of U.S. patent
application Ser. No. 10/851,083 (U.S. Pat. Pub. No. 2004/0211746)
filed May 24, 2004, which is a continuation-in-part of U.S. patent
application Ser. No. 10/444,616 (U.S. Pat. Pub. No. 2003/0196926)
(abandoned) filed on May 23, 2003, which is a continuation-in-part
of U.S. patent application Ser. No. 10/124,734 filed on Apr. 17,
2002, now U.S. Pat. No. 6,612,451, which claims the benefit of
priority of U.S. Provisional Patent Application No. 60/284,795
filed on Apr. 19, 2001. Additionally, PCT application
PCT/US2004/016405 filed May 24, 2004 also claims priority to U.S.
patent application Ser. No. 10/444,616 (U.S. Pat. Pub. No.
2003/0196926) (abandoned). The contents of each of the foregoing
are incorporated by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a base for a wide mouth
blow-molded plastic container, and more particularly, the present
invention relates to a multi-functional base structure which
enables use of the container in hot-fill, as well as
pasteurization/retort processing.
BACKGROUND OF THE INVENTION
[0003] Plastic blow-molded containers, particularly those molded of
PET, have been utilized in hot fill applications where the
container is filled with a liquid product heated to a temperature
in excess of 180.degree. F. (82.degree. C.), capped immediately
after and allowed to cool to ambient temperatures. Plastic
blow-molded containers have also been utilized in pasteurization
and retort processes, where a filled and sealed container is
subjected to thermal processing and is then cooled to ambient
temperatures. Pasteurization and retort methods are frequently used
for sterilizing solid or semi-solid food products, e.g., pickles
and sauerkraut, which may be packed into the container along with a
liquid at a temperature less than 82.degree. C. (180.degree. F.)
and then heated, or the product placed in the container that is
then filled with liquid, which may have been previously heated, and
the entire contents subsequently heated to a higher temperature.
Pasteurization and retort differ from hot-fill processing by
including heating the contents of a filled container to a specified
temperature, typically greater than 93.degree. C. (200.degree. F.),
until the contents reach a specified temperature, for example
80.degree. C. (175.degree. F.), for a predetermined length of time.
Retort processes also involve applying overpressure to the
container. In each of these cases, the plastic containers are
typically provided with vacuum absorption panels to accommodate
volumetric changes in the container as the contents of the sealed
container are heated and/or as the contents cool within the sealed
container.
[0004] U.S. Pat. No. 6,439,413 issued to Prevot et al. and assigned
to Graham Packaging Company, L.P. discloses a hot-fillable and
retortable plastic wide-mouth blow-molded container having a
sidewall with a pair of flex panels.
[0005] Co-pending U.S. patent application Ser. No. 10/129,885 filed
on May 10, 2002 is the U.S. national phase of International
Application No. PCT/US00/31834 is assigned to Graham Packaging
Company, L.P., and discloses a pasteurizable wide-mouth container
having a novel base.
[0006] Other plastic wide-mouth containers having paneled sidewalls
are disclosed in U.S. Pat. No. 5,887,739 issued to Prevot et al,;
U.S. Pat. No. 5,261,544 issued to Weaver. Jr.; and U.S. Pat. No.
5,092,474 issued to Leigner. A pasteurizable plastic container
having paneled sidewalls and a narrow neck finish is disclosed by
U.S. Pat. No. 5,908,128 issued to Krislmakumar et al.
[0007] Containers having non-paneled side s and yieldable end wall
structures are disclosed in U.S. Pat. Nos. 4,642,968, 4,667,454 and
4,880,129 issued to McHenry et al.; U.S. Pat. No. 5,217,737 issued
to Gygax et al.; U.S. Pat. No. 5,234,126 issued to Jonas et al.;
U.S. Pat. No. 4,381,061 issued to Cerny et al.; U.S. Pat. No.
4,125,632 issued to Vosti et al.; and U.S. Pat. No. 3,409,167
issued to Blanchard. The above cited patents disclose containers
having various base structures.
[0008] The structure of a so-called footed base is disclosed, in
general, in U.S. Pat. No. 4,355,728 issued to Yoshino et al., U.S.
Pat. No. 5,713,480 issued to Petre et al., U.S. Pat. No. 3,727,783
issued to Carmichael, U.S. Pat. No. 4,318,489 issued to Snyder et
al., U.S. Pat. No. 5,133,468 issued to Brunson et al., U.S. Pat.
No. 5,024,340 issued to Alberghini et al., U.S. Pat. No. 3,935,955
issued to Das, U.S. Pat. Nos. 4,892,205, 4,867,323 and Re. 35,140
issued to Powers et al., and U.S. Pat. No. 5,785,197 issued to
Slat.
[0009] U.S. Pat. No. 4,321,483 issued to Dechenne et al. discloses
a base having slightly angled annular surface and a central conical
projection; and U.S. Pat. No. 4,386,701 issued to Galer discloses a
blow molded plastic drum having a base which is designed to stack
efficiently with the lid of a like drum.
[0010] Plastic containers, including those described in the
above-mentioned references, containers, including containers
designed for use in hot-fill processing. There remains a need to
provide plastic containers that can withstand the rigors of
pasteurization and retort processing in order to take advantage of
the cost savings that can be realized through manufacture and
recycling. The lighter weight of plastic containers as compared to
glass can also advantageously reduce shipping costs.
[0011] Published international Application No. WO 02/02418
describes a container with a base that can be capable of
withstanding the rigors of the pasteurization process. The base
includes a large push up section formed with a sharp transition to
the container sidewall. The base also must be heat set to a
relatively high crystallinity.
[0012] While the above referenced containers and base structures
may function satisfactorily for their intended purposes, there is a
need for a plastic, wide-mouth, blow-molded container which is
particularly suited for packaging a variety of viscous and other
food products and which has a navel base structure that enables the
container to be utilized in hot-fill, pasteurization and retort
processes. The base structure should be capable of accommodating
increased internal pressure experienced during pasteurization;
capable of accommodating vacuum formed in the sealed container
during cool down; and capable of resisting unwanted inversion,
ovalization or like deformation. A container capable of efficient
stacking with like containers is also desirable.
SUMMARY OF THE INVENTION
[0013] With the foregoing in mind, an object of the present
invention is to provide a commercially satisfactory wide-mouth
blow-molded container that can be utilized in hot-fill
applications, as well as for pasteurization or retort applications
used in for packaging fluent, viscous and solid food products.
[0014] Another object of the present invention is to provide a base
structure capable of accommodating an increase in internal
container pressure when the sealed container is subjected to
thermal treatment, and capable of accommodating vacuum during cool
down.
[0015] Still another object of the present invention is to provide
a hot-fillable and pasteurizable container having a base which
accommodates changes in internal pressure and volume and which
resists unwanted inversion and other deformation.
[0016] A further object of the present invention is to provide a
structure for a wide-mouth plastic container which can be
efficiently stacked, one on top of the other, with like containers
and which can be produced by means of high speed manufacturing
equipment in an economical manner that ensures consistent quality
and performance.
[0017] More specifically, the present invention provides a blow
molded plastic container having a base with a continuous or
discontinuous concave outer annular wall having an outer portion
and an inner portion forming a standing ring therebetween. The base
also includes an inner annular wall that extends within the outer
annular wall and above the standing ring. The inner periphery of
the inner annular wall is made of blow molded plastic material that
is heat-set and biaxially-oriented and connects to an
anti-inverting central dimple. Functionally, the inner annular wall
is capable of flexing upwardly and downwardly in response to
variations in pressures in a filled and sealed container without
undergoing unwanted permanent deformation. In addition, preferably
a shoulder extends radially inward on the inner portion of the
outer annular wall above a level of the standing ring to facilitate
vertical stacking of containers having like bases.
[0018] In a particular embodiment, the container includes a body
having an integrally formed base that includes a concave annular
wall extending from a sidewall of the container to a standing
surface, an inner wall that is substantially perpendicular to the
sidewall and extends from the standing surface to a substantially
flat inner annular wall. The concave annular wall can be
continuous. A dimple is centrally located within the inner annular
wall and includes a plurality of spaced apart radially extending
indented ribs. Each rib has a brace that extends radially from the
dimple and tapers to meet the inner annular wall. The ribs can also
include a rib wall; and a brace ledge tapering from the rib wall to
the inner annular wall, a rib wall; and a brace ledge tapering from
said rib wail to the inner annular wall. A brace sidewall extending
from said brace ledge to said inner annular wall.
[0019] The container can be made of a blow molded plastic material,
and the degree of crystallinity of the plastic material in the base
is greater than the degree of crystallinity one plastic material in
the sidewall. The degree crystallinity in the base can be greater
than 20% an can be less than 30%. The sidewall diameter can be no
more than 50% greater than the inner diameter of the standing
surface.
[0020] The inner annular wall of the base is adapted to flex
upwardly and downwardly in response to variations in pressures
within the container, when capped and filled, without undergoing
unwanted permanent deformation.
[0021] The invention is also a method of improving resistance to
base deformation in a blow molded plastic container comprising
forming a concave annular wall extending from an extremity of the
base to a standing surface, fanning an inner wall extending from
the standing surface to a substantially flat inner annular wall
that is substantially perpendicular to the sidewall; and forming a
centrally located dimple within the inner annular wall and a
plurality of spaced apart radially extending indented ribs, each of
the ribs comprising a brace extending radially from the dimple and
tapering to meet the inner annular wall.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The foregoing and other objects, features and advantages of
the present invention should become apparent from the following
description when taken in conjunction with the accompanying
drawings, in which:
[0023] FIG. 1 is a perspective view of a container having a base
according to embodiment of the present invention;
[0024] FIG. 2 is an elevational view of the container illustrated
in FIG. 1;
[0025] FIG. 3 is bottom plan view of the base illustrated in FIG.
1;
[0026] FIG. 4 is a cross-sectional view of the base taken along
line IV-IV of FIG. 3;
[0027] FIG. 5 is a cross-sectional view of the base taken along
line V-V of FIG. 2 and illustrates a pair of containers in a
stacked arrangement;
[0028] FIG. 6 is a perspective view of a container having a base
according to another embodiment of the invention;
[0029] FIG. 7 is a bottom view of the base according to the
embodiment illustrated in FIG. 6;
[0030] FIG. 8 is a cross-section of the base of FIG. 6 taken along
the VIII-VIII line of FIG. 7;
[0031] FIG. 9 is a cross-section of the base of FIG. 6 taken along
the line IX-IX of FIG. 7;
[0032] FIG. 10 is a perspective view of a container having a base
embodying the present invention;
[0033] FIG. 11 is an elevational view of the container illustrated
in FIG. 10;
[0034] FIG. 12 is bottom plan view of the base illustrated in FIG.
10;
[0035] FIG. 13 is a cross-sectional view of the base taken along
line 4-4 of FIG. 12; and
[0036] FIG. 14 is a cross-sectional view of the base taken along
line 5-5 of FIG. 11 and illustrates a pair of containers in a
stacked arrangement.
DETAILED DESCRIPTION OF THE INVENTION
[0037] An embodiment of the present invention is illustrated in
FIGS. 1-5 as container 100. Container 100 has a base 112, a tubular
sidewall 114, and a wide-mouth threaded finish 116 which projects
from the upper end of the sidewall 114 via a shoulder 118. In the
illustrated embodiment, upper and lower label bumpers, 120 and 122,
are located adjacent the shoulder 118 and base 112, respectfully,
and outline a substantially cylindrical label area 124 on the
sidewall 114. Containers according to the invention can have
cross-sectional shapes other than circular. In addition, the
sidewall 114 can have a series of circumferential grooves 126 which
reinforce the sidewall 114 and resist paneling, dents and other
unwanted deformation of the sidewall 114.
[0038] The container 100 is multi-functional since it can be
utilized in hot-fill as well as pasteurization and retort
processing. To accomplish this objective, the base 112 has a
structure which is capable of accommodating elevated internal
container pressure experienced during pasteurization or retort
processing, and which is capable of accommodating reduced container
volume and pressure experienced upon cool down of a filled and
sealed container after hot-fill, pasteurization or retort
processing. To this end, the base 112 can flex downwardly in a
controlled manner and to a desired extent when pressure within the
filled and sealed container is elevated, and the base 112 can flex
upwardly in controlled manner and to a desired extent when a vacuum
develops within the filled and sealed container.
[0039] Structurally, the base 112 includes a concave outer annular
wall 128 that is either continuous or discontinuous. FIGS, 1-5
illustrate an embodiment of the base 112 having a discontinuous
concave outer annular wall 128 that provides a plurality of
spaced-apart, arcuate supports 130 adjacent the outer periphery 132
of the base 112. Each support 130 has an outer wall portion 134
that extends upwardly toward the lower label bumper 122 and an
inner wall portion 136 that extends upwardly and inwardly into the
remaining base structure as will be discussed. A standing surface
138 is formed at the juncture of each outer and inner wall
portions, 134 and 136, thereby forming a discontinuous support ring
of the container 100. FIGS. 6-9 illustrate an embodiment of a base
212 having a continuous concave outer annular wall 228 that forms a
continuous standing surface 238, as described more fully below.
[0040] An inner annular wall 140 of base 112 extends within the
concave outer annular wall 128. The inner annular wall 140 has an
outer periphery 142 and an inner periphery 144. The outer periphery
142 of the inner annular wall 140 merges with the inner wall
portion 136 of each of the supports 130 and, in the illustrated
embodiment, with a plurality of spaced-apart,
horizontally-disposed, radial webs 146 located adjacent the outer
periphery 132 of the base 112. Each of the webs 146 extends between
the supports 130 and connects to the container sidewall 114 at an
elevation above the horizontal plane "P" extending through the
standing surface 138. In an embodiment of the present invention in
which the concave outer annular wall 128 is continuous, webs 146
are not provided. The inner periphery 144 of the inner annular wall
140 merges into an anti -inverting central dimple 148.
[0041] The inner annular wail 140 functions as a flex panel. To
this end, when the internal pressure increases within a filled and
sealed container, the inner annular wall 140 flexes downwardly to
accommodate the increased pressure and to prevent the sidewall 114
of the container 100 from undergoing unwanted permanent distortion.
In addition, the inner annular wall 140 flexes upwardly to relieve
vacuum when the contents of a hot tilled and capped container, or a
filled, capped and subsequently pasteurized container, cool to
ambient. Thus, when the sealed container and contents cool to
ambient temperature, the sidewall 114 is substantially unchanged
from its as-formed shape and is capable of neatly supporting a
wrap-around label without unwanted voids or the like beneath the
label. In addition, the sidewall 114 resists ovalization and the
base 112 provides a level seating surface which is not subject to
rocking or the like.
[0042] The base 112 of container 100 is specifically designed to
provide flexural movement. Increasing flexure of the base 112 is
accomplished by providing a larger circular flat between the dimple
148 and the arcuate supports 130. Thus, the inner annular wall 140
of container 100 is relatively large compared to other containers
of a similar size. To this end, the diameter, size, or extent of
the central dimple 148 is reduced and the inner diameter of the
arcuate supports 130 is increased relative to prior art
container.
[0043] The relatively large flat surface provided by inner annular
wall 140 provides greater, flexure; however, it can also be more
prone to "roll out", i.e. becoming permanently deformed in an
outwardly projecting position when its contents are hot-filled or
heated at relatively high temperatures, such as those encountered
during pasteurization or retort processing. This is because an
amorphous ring of material is created at the interconnection of the
inner periphery 144 of the inner annular wall 140 and the dimple
148 due to the reduced size of the dimple 148. This ring of un
oriented, non heat-set material provides a weakened area that
permits the base to "roll out" when filled and sealed with contents
at high temperatures.
[0044] The base 112 of the present invention overcomes the "roll
out" problem by providing a series of spaced-apart,
radially-extending, hollow, indented ribs 150 in the dimple 148
where the inner periphery 144 of the inner annular wall 40
interconnects to the central dimple 148. The structure provided by
the ribs 150 causes the material in this region to be stretched
during blow molding of the container 100 so that the ring of
material adjacent the interconnection of the dimple 148 and inner
annular wall 140 is both heat-set and the extent of biaxial
orientation increased to structurally reinforce the base and
prevent "roll out" of the base 112. If desired, the dimple 148 can
be indented to a given extent into the container 100 to provide
additional stretching, and the total number of ribs 150 can be
three or more, such as six as illustrated in FIG. 1. In addition,
the shape and size of the ribs can vary as long as the blow molded
plastic material forming the base at the interconnection of the
dimple 148 and inner annular wall 140 has sufficiently increased
biaxial orientation and is heat-set by heated surfaces of a blow
mold.
[0045] Thus, the inner annular wall 140 flexes downwardly when the
container is filled, capped and subjected to an increase in
pressure within the container. However, complete inversion and
failure is prevented by the reinforcement ribs 150 formed in the
dimple 148, which travel with the inner annular wall 140. The ribs
150 and dimple 148 maintain a substantially constant shape
regardless of the internal pressure experienced within the
container, due to the increase in density and stiffness resulting
from the increased orientation.
[0046] Another feature of the base 112 of the present invention is
that each inner wall portion 136 of the arcuate supports 130 can
have an arcuate shoulder, or support ridge, 156 formed therein and
spaced in elevation from both the support surfaces 138 and the
inner annular wall 140 to facilitate vertical stacking of like
containers 100. For example, as illustrated FIG. 5, an upper
container 100a can be stacked on a lower container 100b. The
support ridge 156 in the base 112a of the upper container 100a
seats on the outer edge 158 of the upper surface 160 of the lid 162
of the lower container 100b such that the horizontal plane
"P.sub.a" extending through the standing surfaces 138a of the upper
container 100a extends a spaced distance beneath the top surface
160 of the lid 162 of the lower container 100b.
[0047] By way of example, and not by way of limitation, the
container 100 according to the present invention preferably has a
height "H" of about 5.8 inches, a container outermost diameter "D"
of about 4.2 inches, and can contain a capacity of about 32 fluid
ounces. The discontinuous standing ring formed by the standing
surfaces 38 has a diameter of about 3.7 inches, and the inner
annular wall 140 of the base 112 has an inner periphery 144 with a
diameter of less than about 1.25 inches and an outer periphery 142
with a diameter of at least about 2.5 inches. The radial webs 146
are uniformly spaced apart and separate each support 130 such that
each support 130 is at least about 0.8 radians. In addition, each
support 130 has a larger arcuate extent than that of each radial
web 146.
[0048] FIGS. 6-9 illustrate a second embodiment of a base 212 that
may be used on a container 200 according to the present invention.
Other than the base 212, the container 200 can be the same as or
different from container 100. Accordingly, the last two digits in
reference numerals used to designate features of the container 200
are the same as the reference numerals that are used to designate
the related features container 100. For example, the container 200
can include a threaded finish 216 that can be the same as the
threaded finish 116 of the first embodiment, and can accommodate a
closure 262 having complemental threads. Similarly, the shoulder
218, upper bumper 220, circumferential grooves 226, label area 224,
and sidewall 214 can be structurally similar to the corresponding
features of the first embodiment.
[0049] The second embodiment of the base 212 includes a continuous
concave outer annular sidewall 228. The outer portion 228 of the
annular sidewall curves from the sidewall 214 toward the center of
the container 200 to fetal a continuous standing surface 238. The
standing surface 238 is formed as a continuous, circular surface.
Further, the transition from the outer annular sidewall 228 to the
standing surface 238 is gradual and continuous. An inner portion
236 of the outer annular sidewall extends from the standing surface
238 to a substantially flat inner annular wall 240. The outer
periphery 242 of the inner annular wall 240 forms a continuous ring
around the inner annular wall 240.
[0050] Approximately centrally located on the inner annular wall
240 is a dimple 248. Extending outwardly from the dimple 248 are a
series of ribs 250. The dimple 248 of this embodiment can be
substantially the same size as the dimple 148 in the first
embodiment 100, or can be slightly larger. The ribs 250 of the
second embodiment extend outwardly to form a series of radially
placed braces 270, which taper to an elevation that meets the flat
inner annular wall 240 before, near, or the outer periphery 242 of
the inner annular wall. In the illustrated embodiment, the ribs 250
first extend outward from the dimple at a similar depth to the
inner portion 272 of the dimple to a rib wall 274, where there is a
relatively abrupt change in depth toward the inner annular wall
240. The rib wall 274 extends up to a brace ledge 276 which slopes
towards the surface of the inner annular wall 240. The brace ledge
276 can meet the surface of the inner annular wall 240 at or before
the outer periphery 242. The sidewall of the brace 278 extends
upward from the brace ledge 276 to the surface of the inner annular
wall 240. The brace sidewall 278 meets the inner annular wall 240
at a periphery of the brace 270. The sidewall of the brace 278 can
be substantially perpendicular to the inner annular wall 240 and
the brace ledge 276.
[0051] The inner annular wall 240 in base 212 flexes in a manner
analogous to the inner annular wall 140 of base 112. The radially
spaced braces 270 further control flexure of the annular wall 240
in response to the reduced pressures that occur when the container
cools down daring hot-fill processing, and the reduced and
increased pressures that occur during pasteurization and retort
processing. The presence of the braces 270 allows greater flexure
of the inner annular wall 240 within the concave outer annular wall
228 without allowing permanent deformation of the base. In
addition, the presence of a continuous outer annular wall 228 is
useful during rigorous pasteurization or retort conditions. Under
such conditions, a discontinuous outer sidewall that has feet can
have a tendency for the feet to pull in, causing the lower bumper
to move into a square shape. By having a continuous standing
surface 238 and a continuous outer annular sidewall 228, this
tendency is reduced. Further, the presence of a continuous standing
surface 238 alleviates any tendency for excessive base rollout.
[0052] The base structure described herein is illustrated without a
support ridge 156 (see FIGS. 1-5) for stacking of containers. Such
a ridge o shoulder can, however, be readily incorporated into a
base 242 according to this second embodiment of the invention.
[0053] The base 212 according to the present invention is
preferably crystallized to some extent as previously described in
the first embodiment. Some degree of crystallinity and biaxial
orientation is achieved normally during the blow molding process.
Crystallization can also be promoted through heat setting of the
container. For example, the walls and base of the mold can be held
at an elevated temperature to promote crystallization. When the
container is heat set at a temperature of about 180.degree. F., the
container sidewalls, base, dome, and threads can be typically
crystallized to about 20%. This degree of crystallinity is typical
for a blow molding process and does not represent a significant
amount of heat setting or increased crystallinity or orientation,
as compared with a typically prepared container. However, the
properties of the base of the present invention can he
advantageously enhanced by heat setting the container, and
particularly the base, at ever higher temperatures. Such
temperatures can be, for example, greater than 250.degree. F. and
can be 325.degree. F. or even higher. When these elevated heat set
temperatures are utilized, crystallinity can be increased to
greater than 20% or 25% or more. One drawback of increasing
crystallinity and biaxial orientation in a plastic container is
that this process introduces opacity into the normally clear
material. However, unlike bases in prior art containers designed
for use in pasteurization and retort processes, which can require a
crystallinity of 30% or more, utilizing crystallinitics of as low
as 22-25% with a base structure according to the present invention
can achieve significant structural integrity, while maintaining the
substantial clarity of a base that is preferred by manufacturers,
packagers and consumers of such pasteurized commodities.
Crystallinities of 30% or greater that are frequently utilized in
prior container to achieve significant structural integrity can
cause undesirable opacity in the base region.
[0054] Bases formed with configurations according to the present
invention provide a more appealing structure to consumers,
packagers and manufacturers for other reasons, as well. For
example, when switching from the use of glass to plastic in
packaging such pasteurizable commodities, design changes cause
undesirable changes in the internal container configuration.
Typically, in order to withstand the rigors of pasteurization or
retort processing, prior containers have included a base formed
with a large central push-up, as is used in typical plastic
containers used in hot-fill processes. This push-up limits the
volume of material that can be placed in the container in the
internal region between the push-up and the sidewalls. This can be
particularly problematic when solid products, for example, pickles,
are packaged. The presence of narrow channels which are formed
between the sidewall and large base push-up in the internal space
of a typical blow molded container, can limit the volume into which
solid materials can he placed. That is, such designs create dead
space within the container that can be filled by liquid, but not by
the solid product. In traditional glass containers, a relatively
flat bottom can he formed which allows solids to be packed
throughout the vertical and radial extent of the container. Prior
art plastic containers that have been utilized to withstand the
pasteurization and retort conditions have used similar internal
geometry, which creates dead space.
[0055] According to the present invention, and particularly
according to the second embodiment described herein, the
configuration of the base can reduce the amount of dead space and
be much more similar to traditionally used glass containers. For
example, the substantially flat inner annular wall 240 can extend
to a substantial outward extent toward the edge of the container.
By using a base configuration according to the present invention,
the inner diameter of the standing surface, i.e. the pushed-up
region of the base D.sub.1, as shown in FIG. 9, can be a relatively
large portion of the container diameter D.sub.2. According to the
present invention, the ratio of the container diameter D.sub.2 to
the pushed-up diameter D.sub.1 can be less than 1.5:1.0 and even
1.3:1.0 or lower. Stated differently, the diameter of the container
D.sub.2 can be less than 50% larger than, or as little as about 30%
larger than, the diameter of D.sub.1 of the pushed-up region. In
cases where the container not round, this corresponds to a
projected volume of the sidewall region less than 70% greater than
the projected area of the push-up region.
[0056] By way of example, and not by way of limitation, the
container 200 according to the present invention can have
dimensions similar to those of the container 100. For example, the
container can have a height of about 5.8 inches, an outermost
diameter D.sub.2 of about 3.8 inches, and can contain a capacity of
about 32 fluid ounces. The pushed-up region of the base can have a
diameter D.sub.1 of about 3.1 inches. The brace 270 can have a
brace ledge 276 that extends out about 0.6 inches from the dimple
248. The distance between opposite rib wails 274 can he about 1.2
inches, while the distance across the dimple 248 in the region
between ribs can be about 0.9 inches.
[0057] The containers 100 and 200 can be blow molded from an
injection molded preform made from, for example, PET, PEN or blends
thereof, or can be extrusion blow molded plastic, for example,
polypropylene (PP). In addition, the containers 100 and 200 can be
multilayered, including a layer of gas barrier material or a layer
of scrap material. Resins also include polyester resins modified to
improve UV resistance, for example Heatwave.TM. CF246, available
from Voridian (Kingsport, Tenn., U.S.A.). The finishes of the
containers can be injection molded, i.e. the threaded portion can
be formed as part of the preform, or can be blow molded and severed
from an accommodation feature formed thereabove, as is known in the
art.
[0058] The above described containers 100 and 200 are capable of
use, for instance, in hot-fill operations having fill temperatures
up to about 205.degree. F. As explained above, containers 100 and
200 having base 112 and 212 can be utilized when processing
temperatures approach or exceed 205.degree. F. The containers can
also be utilized in typical pasteurization processes used in the
packaging art. In an exemplary process, a cold solid product, such
as pickles, is combined with mildly heated brine at 120 to
140.degree. F. within the container. After the container is capped,
the filled container can be processed through a pasteurization
tank, where temperatures approach about 212.degree. F., so that the
solid products in the sealed container are heated to approximately
175.degree. F. for 15 minutes before the filled and sealed
container is cooled to ambient temperature.
[0059] The present invention provides a container 10 which is
particularly suited for use as a jar for packaging food products.
For example, the container 10 can be used to package fluent or
semi-fluent food products such as applesauce, spaghetti sauce,
relishes, sauerkraut, baby foods, and the like. It can also be used
to package a solid food product suspended in a liquid brine, such
as pickles. Thus, the container 10 can be utilized for packaging
various food products and can withstand various fill and treatment
operations, as will be discussed.
[0060] As illustrated in FIG. 10, in one preferred embodiment of
the present invention a container 10 is provided having a base 12,
a substantially cylindrical sidewall 14, and a wide-mouth threaded
finish 16 which projects from the upper end of the sidewall 14 via
a shoulder 18. Preferably, as illustrated, upper and lower label
bumpers, 20 and 22, are located adjacent the shoulder 14 and base
12, respectfully, and outline a substantially cylindrical label
area 24 on the sidewall 14. Thus, a label (not shown) can be
attached to, and extend completely around, the container sidewall
14. In addition, preferably the sidewall 14 has a series of
circumferential grooves 26 which reinforce the cylindrical shape of
the sidewall 14 and resist paneling, dents and other unwanted
deformation of the sidewall 14.
[0061] The container 10 is multi-functional since it can be
utilized in hot-fill as well as pasteurization/retort processing.
To accomplish this objective, the base 12 has a structure which is
capable of accommodating elevated internal container pressure
experienced during pasteurization/retort processing and which is
capable of accommodating reduced container volume experienced upon
cool down of a filled and sealed container after hot-fill or
pasteurization/retort processing. To this end, the base 12 flexes
downwardly in a controlled manner and to a desired extent when
pressure within the filled and sealed container is elevated, and
the base 12 flexes upwardly in a controlled manner and to a desired
extent when a vacuum develops within the filled and sealed
container.
[0062] Structurally, the base 12 includes a discontinuous concave
outer annular wail 28 which provides a plurality of spaced-apart,
arcuate supports 30 adjacent the outer periphery 32 of the base 12.
As illustrated, four supports 30 are utilized in the preferred
embodiment; however, three, five or more supports 30 could also be
utilized. Each support 30 has an outer wall portion 34 which
extends upwardly toward the lower label bumper 22 and an inner wall
portion 36 which extends upwardly and inwardly into the remaining
base structure as will be discussed. A standing surface 38 is
formed at the juncture of each outer d inner wall portions, 34 and
36, thereby framing a discontinuous support ring of the container
10.
[0063] An inner annular wall 40 extends within the discontinuous
concave outer annular wall 28 and is preferably slightly inclined
relative to the horizontal. Preferably, the inclined inner annular
wall 40 extends upwardly and inwardly at an angle "A" relative to
the horizontal as it extends from its out periphery 42 to its inner
periphery 44. For example, the inner annular wall 40 can incline at
an angle "A" in a range of about 5.degree. to about 6.degree.
relative to a horizontal plane "P" extending through the standing
surfaces 38. Alternatively, the inner annular wall 40 can be formed
substantially planar and parallel to a horizontal plane "P"
extending through the standing surfaces 38.
[0064] The outer periphery 42 of the inner annular wall 40 merges
with the inner wall portion 36 of each of the supports 30 and with
a plurality of spaced-apart, horizontally-disposed, radial webs 46
located adjacent the outer periphery 32 of the base 12. Each of the
webs 46 extends between the supports 30 and connects to the
container sidewall 14 at an elevation above the horizontal plane
"P" extending through the standing surfaces 38. The inner periphery
44 of the inner annular wall 40 merges into an anti-inverting dome
48 which projects upwardly into the container 10. Preferably, the
inner annular wall 40 and anti-inverting dome 48 merge via an
annular hinge 50. As illustrated in FIG. 13, the anti-inverting
dome 48 has a conical lower portion 52 adjacent hinge 50 and a
convex upper portion 54.
[0065] The inner annular wall 40 functions as a flex panel. To this
end, when die internal pressure increases within a filled and
sealed container, the inner annular wall 40 flexes downwardly as
shown in dashed lines "B" in FIG. 13 to accommodate the increased
pressure and prevent the side wall 14 of the container 10 from
undergoing unwanted permanent distortion. In addition, the inner
annular wall 40 flexes upwardly to relieve vacuum when the contents
of a hot filled and capped container, or a filled, capped and
subsequently pasteurized container, cool to ambient. This is shown
in dashed lines "C" in FIG. 13. Thus, when the sealed container and
contents cool to ambient, the sidewall 14 is substantially
cylindrical and unchanged from its as-formed shape and is capable
of neatly supporting a wrap-around label without unwanted voids or
the like beneath the label. In addition, the sidewall 14 resists
ovalization and the base 12 provides a level seating surface which
is not subject to rocking or the like.
[0066] The anti-inverting dome 48, the supports 30 and the radial
webs 46 support the inner annular wall 40 and permit it to flex
only within a desired range of movement as illustrated by dashed
lines "B" and "C". For instance, the inner annular wall 40 flexes
downwardly due to an increase in pressure within the container, but
is prevented from complete inversion and failure by the
anti-inverting dome 48 which travels with the inner annular wall 40
but substantially maintains a constant shape regardless of the
internal pressure experienced within the container.
[0067] Another feature of the base 12 of the present invention is
that each inner wall portion 36 of the arcuate supports 30 has an
arcuate shoulder, or support ridge, 56 formed therein and spaced in
elevation from both the support surfaces 38 and the inner annular
wall 40 to facilitate vertical stacking of like containers 10. For
example, as illustrated FIG. 14, an upper container 10a is stacked
on a lower container 10b. The support ridge 56 in the base 12a of
the upper container 10a seats on the outer edge 58 of the upper
surface 60 of the lid 62 of the lower container 10b such that the
horizontal plane "Pa" extending through the standing surfaces 38a
of the upper container 10a extends a spaced distance beneath the
top surface 60 of the lid 62 of the lower container 10b.
[0068] By way of example, and not by way of limitation, the
container 10 according to the present invention preferably has a
height "H" of about 5.8 inches, a container outermost diameter "D"
of about 4.2 inches, and contain a capacity of about 32 fluid
ounces. The discontinuous standing ring formed by the standing
surfaces 18 has a diameter of about 3.6 inches, and the inner
annular wall 40 of the base 12 has an inner periphery 44 with a
diameter of about 1.6 inches and an outer periphery 42 with a
diameter of about 2.2 inches. The radial webs 46 are uniformly
spaced apart and separate each support 30 such that each support 30
is at least about 0.8 radians. In addition, each support 30 has a
slightly larger arcuate extent than that of each radial web 46.
[0069] Preferably, the container 10 is blow molded from an
injection molded preform made of PET, PEN or blends thereof or is
extrusion blow molded of PP. In addition, the container 10 may be
multilayered including a layer of gas barrier material or a layer
of scrap material. Preferably, the finish 16 of the container is
threaded, blow molded, and severed from an accommodation feature
formed thereabove.
[0070] The above described container 10 is capable of use in
hot-fill operations having fill temperatures up to 205.degree. F.
It can also be utilized in pasteurization processes wherein a cold
solid product, such as pickles, is combined within the container 10
with mildly heated brine at 120 to 140.degree. F. After the
container 10 is capped, the filled container can be processed
through a pasteurization tat* where temperatures approach about
212.degree. so that the solid products in the sealed container are
heated to approximately 175.degree. F. for 15 minutes before the
filled and sealed container is cooled to ambient temperature.
[0071] While preferred containers and base structures have been
described in detail, various modifications, alterations and changes
may be made without departing from the spirit and scope of the
present invention as defined in the appended claims.
* * * * *