U.S. patent application number 10/086004 was filed with the patent office on 2003-08-28 for liquid container.
Invention is credited to McKenna, David J., Muise, Herbert D., Philips, Nicholas A., Springhorn, Michelle A., Wallick, Scott A..
Application Number | 20030160092 10/086004 |
Document ID | / |
Family ID | 27753771 |
Filed Date | 2003-08-28 |
United States Patent
Application |
20030160092 |
Kind Code |
A1 |
Philips, Nicholas A. ; et
al. |
August 28, 2003 |
Liquid container
Abstract
A shipping container for liquids is described. This consists of
an outer corrugated paperboard container containing an inner
corrugated liner forming corner posts. A flexible or semi-flexible
bladder or jug generally conforming in cross section to the inside
of the corrugated container contains the liquid. It is desirable
for the inner corrugated liner to be bonded to the outer container,
especially along the margins of the corner posts. It has been found
to be critical that the ratio of the length of the outside face of
the outer container to the corner post length should be no greater
than about 8:1. This is essential to prevent face bulging,
especially when the inner plastic container is filled with a high
density material such as a paint. Where the inner plastic container
has an upstanding handle or spout it is useful to have filler
pieces that bear between the plastic container and upper flaps of
the outer corrugated container. This prevents any up and down
motion of the inner container during normal handling or under the
severe stresses that might be imposed on a paint shaker.
Inventors: |
Philips, Nicholas A.; (Sugar
Grove, IL) ; Wallick, Scott A.; (Seattle, WA)
; McKenna, David J.; (Lacey, WA) ; Muise, Herbert
D.; (Tumwater, WA) ; Springhorn, Michelle A.;
(West Dundee, IL) |
Correspondence
Address: |
WEYERHAEUSER COMPANY
INTELLECTUAL PROPERTY DEPT., CH 1J27
P.O. BOX 9777
FEDERAL WAY
WA
98063
US
|
Family ID: |
27753771 |
Appl. No.: |
10/086004 |
Filed: |
February 26, 2002 |
Current U.S.
Class: |
229/122.32 ;
229/117.24 |
Current CPC
Class: |
B65D 5/5045 20130101;
B65D 77/065 20130101 |
Class at
Publication: |
229/122.32 ;
229/117.24 |
International
Class: |
B65D 005/46 |
Claims
1. A container for liquid materials which comprises an inner
flexible liquid-tight plastic container and an outer corrugated
paperboard container, the outer container being generally
rectangular in cross section and having top, bottom and sidewall
portions; an octagonal secondary sidewall having face and corner
sections snugly inserted within the outer container so as to form
vertically oriented corner posts; the inner plastic container as
seen in cross section being of an octagonal cross section so as to
fit conformingly within the secondary sidewall, the plastic
container having a spout and an optional handle on an upper surface
and being accessible through the top portion of the outer
corrugated container.
2. The container of claim 1 in which the ratio of length of any
face of the outer container to the length of the corner sections of
the secondary sidewall is no greater than about 8:1.
3. The container of claim 2 in which the ratio of length of any
face of the outer container to the length of the corner sections of
the secondary sidewall is within the range of about 3.3:1 to about
8:1.
4. The container of claim 1 in which the secondary sidewall is
adhesively bonded to the outer corrugated container.
5. The container of claim 1 in which there is a space between the
top of the outer corrugated container and the inner plastic
container, the space being sufficient to accommodate the spout and
a handle, if one is present.
6. The container of claim 5 in which there is at least one filler
piece between the top of the inner plastic container and top of the
corrugated outer container to restrain relative motion between the
two.
7. The container of claim 6 in which the spout is centrally located
adjacent an edge of the inner container and the filler piece
comprises two sections, one section being located on each side of
the spout.
8. The container of claim 7 in which the filler piece sections are
of separate construction from the top of the outer corrugated
container.
9. The container of claim 7 in which the filler piece sections are
integral with the top flaps of the outer corrugated container.
10. The container of claim 1 in which the inner plastic container
has an upper surface and an upstanding handle, an inner plastic
container rotation control means being located above the upper
surface, the rotation control means being formed from corrugated
paperboard and sized to bear against the walls of the outer
container, the paperboard having apertures permitting passage of
the spout and the handle of the inner plastic container.
11. The container of claim 10 in which the inner plastic container
handle is generally in the form of an inverted U with upstanding
legs and a connecting cross piece, the rotation control means
having apertures permitting passage of the legs of the handle, the
apertures being connected by a slit to permit the cross piece of
the handle to be pushed through for access.
12. The container of claim 6 in which the inner plastic container
has an upper surface and an inner plastic container rotation
control means located between the upper surface and the filler
piece or pieces.
13. The container of claim 12 in which the inner plastic container
has an upstanding handle and the rotation control means is formed
from corrugated paperboard sized to bear against the walls of the
outer container, the paperboard having apertures permitting passage
of the spout and the handle of the inner plastic container.
14. The container of claim 13 in which the inner plastic container
handle is in the form of an inverted U with upstanding legs and a
connecting cross piece, the rotation control means having apertures
permitting passage of the legs of the handle, the apertures being
connected by a slit to permit the cross piece of the handle to be
pushed through for access.
15. The container of claim 1 in which the spout and optional handle
may be formed or telescoped within the top of the inner plastic
container and the top of the inner plastic container is flush with
and contacts the top flaps of the outer corrugated container.
Description
[0001] The present invention is directed to a shipping container
for liquids. This is of the type in which a thin plastic inner
container for the liquid is placed within a corrugated outer
container for structural rigidity and protection. The container is
particularly suitable for products such as paints that must be
severely agitated in the container to disperse and homogenize the
contents before use.
BACKGROUND OF THE INVENTION
[0002] It has been common practice for many years to ship liquid
materials contained within plastic bags enclosed in a rigid outer
container. One might note U.S. Pat. No. 4,174,051 to Edwards et al.
as an example. This patent shows a corrugated box containing a
flexible plastic inner container with a pull-up spout for filling
and dispersing the liquid contents.
[0003] Rutter, U.S. Pat. No. 4,322,018, is primarily directed to a
valve with means to pierce an otherwise imperforate bag at the time
of use. The patent shows a liquid filled bag within a corrugated
paperboard container having a keyhole-shaped portion that can be
opened for access to the valve.
[0004] Cox, Jr., in U.S. Pat. No. 3,100,587 shows a liquid
container having a plastic bag within a containerboard box. The bag
has a capped pouring tube affixed by a wire tie to a tab on one of
the inner upper flaps of the container. When the overlying outer
flap is opened the tab with its affixed tube is exposed.
[0005] Nichols, in U.S. Pat. No. 5,029,734, shows a reusable pallet
mounted molded plastic container enclosed within a reinforcing
containerboard shell. Similarly, Perkins, in U.S. Pat. No.
5,813,562, is another pallet mounted container having an interior
collapsible plastic bag within exterior multiwalled containerboard
in the form of a regular octagon. This particular construction
enables the bag, with a lower drain, to be conveniently installed
from the bottom of the exterior container.
[0006] Containers having a bag within a box and permanently mounted
exterior spouts have also been used for many years. Exemplary among
these might be noted the following U.S. patents: Parker, U.S. Pat.
No. 2,973,119; McCullough et al., U.S. Pat. No. 4,696,840; Gordon
et al., U.S. Pat. No. 5,156,295; and Voorhies Jr., U.S. Pat. Nos.
4,793,519 and 4,930,661.
[0007] Baker, in U.S. Pat. Nos. 5,348,186 and 5,474,203, shows a
bag within a multipiece octagonal exterior corrugated container.
These patents are especially directed to a construction that
maintains an upper spout locked in place to accept a hand pump.
Openings at the top of the container allow it to be handled by a
conventional barrel hand truck. A similar plastic bag within an
octagonal corrugated outer container is shown in Benner et al.,
U.S. Pat. No. 5,749,489, although in this case the inner container
has a bottom drain.
[0008] More commonly, liquid materials in larger quantities have
been shipped within metal drums or in metal or plastic buckets of
various sizes. Buckets are frequently of about 5 gallon (.about.20
L) capacity so that they can be readily handled. When shipping
paints and other compositions that may contain a significant
percentage of suspended solid materials, these buckets typically
have removable heads covering the entire top. Again using paints as
an example, the buckets are palletized for shipping and at the
point of use individual buckets may be placed on a shaker to
disperse the pigment and/or other solid components. The action of
the shaker is quite violent, as anybody who has observed a smaller
shaker in a paint store can testify.
[0009] Containers must be capable of withstanding severe forces
during shipping and use. There are significant disadvantages to
shipping palletized buckets. Foremost among these are the
inefficient use of space on the pallet and the hazard of the
outermost buckets inadvertently slipping off the edges. Depending
on the particular bucket size and configuration on the pallet, as
much as half of the pallet surface may be underutilized. Another
disadvantage is that the upper surface of the buckets provides an
unstable and irregular bearing surface for stacking additional
pallets. One proposed solution to the above problems has been to
ship the paint within a plastic bag contained in a corrugated
paperboard shipping container. This has had only limited success
for a number of reasons. The entire inner and outer container must
be strong enough to withstand stacking and the action of the
shaker. Many times the material shipped is a tint base and various
customized pigments are added at the point of use and the inner
container must be able to accommodate this added material. If the
inner container is not completely filled the contained liquid can
slosh violently back and forth during shaking. For this reason, and
to exclude air from leftover contents, the inner container is
usually flexible enough so that it can be partially collapsed after
partial removal of the contents.
[0010] It is highly undesirable to have to open the top flaps of
the container for access to the spout; e.g., to add pigment. The
container then loses much of the strength needed on the shaker and
during subsequent handling, as when the container is picked up to
pour paint into a smaller working container. Cartons may be
designed with an opening for the spout, as in the aforenoted
Edwards et al. patent, but these are effective only if the spout is
always located exactly under the opening. During shipping, and
especially during shaking, there is a strong tendency for the
filled bags to rotate within the container so that an originally
properly located spout is then nowhere to be found without tearing
open the top flaps. Rotation during shaking can also result in
abrasion and failure of the inner bag.
[0011] The present invention overcomes the deficiencies just noted
and provides an effective plastic container-within-a-box for paints
and many other liquid materials.
SUMMARY OF THE INVENTION
[0012] The invention is a shipping container for liquid materials
comprising the combination of a relatively lightweight liquid tight
flexible or semi-flexible bladder or jug within a corrugated
paperboard outer carton. An upper access spout with a removable cap
is normally integral with the jug. The construction is designed to
minimize relative motion between the inner plastic portion and the
outer corrugated container during use. This use may vary from low
energy routine handling to high energy shaking. By minimizing
relative motion between the inner plastic container and outer
corrugated paperboard, any tendency to create stress points and
form leaks in the plastic inner container is controlled.
[0013] In the past with bag-in-a-box construction, the inner
plastic containers have usually been a simple rectangular flat bag
within a conventional corrugated container. Alternatively, a
blow-molded jug having a rectangular cross section with rounded
corners has been used. When such a container is used for paint it
must be able to withstand severe shaking at the time of use to
uniformly disperse the pigments. This is an extreme requirement for
a container. Not only must it have sufficient strength to permit
stacking multiple heavy units, it be strong enough to withstand
rough handling on the shaker. Further, it must retain sufficient
strength even the extreme humidity of a Southeastern summer. It is
well established that at 90% relative humidity the edge compression
strength of most corrugated board drops to about half that at 50%
R.H.
[0014] When attempts have been made to package paint in a
bag-in-a-box-type container, the bags or jugs have been subject to
failure during shaking. This failure might be as minor as pin hole
leaks or as major as catastrophic tears. Neither is acceptable. A
significant part of the problem appears to be due to movement of
the plastic container within the outer box during shaking. In one
attempt to make a more satisfactory paint container, a conventional
blow molded bladder or jug was placed in a corrugated container
having corner posts. This construction initially failed. As the
plastic container attempted to conform to the corner posts, the
resulting wrinkles or folds created stress points that led to
pinhole failures. Further, bulging of the corrugated box sidewalls
permitted excessive movement of the paint filled bladder within the
container. Bulging, in effect, increases the volume of the
corrugated container and allows the inner plastic container to
rotate and/or bounce up and down. In addition to causing leaks,
this bouncing or rotation can occur at a frequency that will
significantly increase the load on the shaker to the point that the
motor will overload and shut down.
[0015] A major solution to the above problems has been the use of
corner posts in the corrugated outer container that are
sufficiently long to prevent face bulging during shaking. A second
part of the solution is to use an inner plastic container that will
closely conform in cross section to the inside of the outer
corrugated container in order to eliminate the wrinkling or
creasing and subsequent leak formation.
[0016] The shipping container overall is configured as a
rectangular parallelepiped which may be square or rectangular when
seen in plan view. An outer corrugated portion will be of
sufficiently heavy one-piece construction as could be easily
determined by a skilled packaging engineer. The outer portion has a
conventional side wall section and top and bottom sections
comprising overlapping flaps. This is fitted with a snugly fitting
interior insert comprising a corrugated secondary sidewall with
truncated corners so that it is octagonal in plan view. The
secondary sidewall provides reinforcement of the outer sidewalls
while the truncated corners act as vertically oriented corner
posts. Most preferably, the secondary sidewall is adhesively bonded
to the outer container, at least along the margins of the corner
posts. As seen in plan view, the ratio of the length of the
sidewalls of the outer container to the length of the corner
sections of the interior insert had been found to be critical. This
should be no greater than about 8:1 and will fall within the range
of about 3.3:1 to 8:1. Construction within this ratio is essential
to prevent bulging of the face portions that might be caused by the
high stresses experienced during shaking of container filled with a
heavy material such as paint. The length of the corner posts must
be sufficient, within the 3.3:1 to 8:1 range, to prevent sidewall
bulging, but preferably the length is held to the minimum necessary
to reduce lost space within the container.
[0017] The inner liquid tight plastic container will normally have
an integral spout for filling and accessing the contents and may,
optionally, have an integrally molded handle. Both spout and
handle, if present, may be permanently upstanding or they may be
conventionally formed or telescoped down below the top surface of
the container. In the case where the spout and handle are
upstanding, there will normally be a space between the inner
plastic container and the upper flaps of the outer corrugated
container. This space is necessary so that the spout and handle do
not protrude above the top surface where they would interfere with
stacking. The area of this space should be wholly or in part filled
with a filler piece or pad to reduce or prevent vertical
displacement of the plastic container during handling or shaking.
It is also desirable to have some means within this space to
restrain rotation of the jug or bladder. The filler pieces may be
as simple as several thickness of containerboard. Material for
their construction is not critical and there are many options
besides containerboard. These may be separate from the main outer
container or may be integrally formed on opposing upper flaps.
Preferably they are located symmetrically on either side of the
spout, the spout normally being located centrally along one edge of
the top surface of the jug. Normally the filler pieces would be
bonded into place to prevent movement during handling or shaking.
If the spout and the handle, if one is present, are recessed below
the upper surface of the plastic container the filler pieces are
unnecessary and the top flaps of the outer corrugated container can
be located directly against the upper surface of the plastic
container.
[0018] The plastic jug or bladder would normally be blow molded
from polyethylene or a similar material. Preferably it should have
sufficient flexibility so that it can be at least partially
collapsed prior to filling or following withdrawal of some of the
contents. This flexibility is desirable to minimize the amount of
space required to inventory the containers prior to filling and for
ultimate disposal.
[0019] The invention thus consists of an outer corrugated
container, an inner octagonal secondary corrugated sidewall forming
corner posts, and a space conforming octagonal liquid-tight plastic
inner container. The ratio of the lengths of the face portion of
the outer container sidewall to the corner sections should be no
greater than about 8:1.
[0020] It is an object of the invention to provide a container for
liquids that is lightweight, disposable, and which will withstand
severe external forces during shipping and downstream handling.
[0021] It is another object to provide a container for liquids
having an inner plastic container within a corrugated outer
shipping container.
[0022] It is a further object to provide a container for paints
that is resistant to developing leaks when the contents are
dispersed on a shaker.
[0023] It is yet an object to provide a paint container that will
withstand the forces delivered by a paint shaker yet will not
induce an excessive load on the shaker motor or mechanism.
[0024] It is an additional object to provide a container for
liquids that is collapsible when empty to minimize storage space
for the containers before and after use.
[0025] These and many other objects will become readily apparent
upon reading the following detailed description taken in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is an exploded view of the container of the present
invention.
[0027] FIG. 2 is a perspective view showing the assembly steps of
the container of FIG. 1.
[0028] FIGS. 3 and 4 show alternative top spacer units for the FIG.
1 container.
[0029] FIG. 5 is an exploded view of an alternative configuration
in which the interior container handles are depressed so that they
are flush with the upper surface.
[0030] FIGS. 6 and 7 show the assembled package using the interior
container of FIG. 5.
[0031] FIG. 8 shows an additional design for the spacer units for
the FIG. 1 container.
[0032] FIG. 9 illustrates an alternative construction for the
bladder rotation means.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Referring now to the drawings, FIG. 1 shows the container of
the present invention. This comprises an outer corrugated box 2
having face panels 4 and upper flaps 6, 6', and 8, 8'. Similar
flaps, not shown, are present to form a bottom closure. An insert
portion 10, also of corrugated board, fits snugly within outer box
2. The insert has face panels 12 and truncated corners 14 that
serve as top-to-bottom corner posts. The insert can be formed from
one or more individual pieces and is most preferably adhesively
bonded to the outer box, especially along the edges of the corner
posts. A blow molded or similarly formed semi-flexible octagonal
plastic bladder or jug 16 fits snugly within the corrugated insert
10. The jug has face portions 18 and corner sections 20 that
correspond to and are closely configured to the interior of insert
10. A spout and cap 22 are located on the upper surface of the jug,
as is an optional handle 24. Above the jug is an optional sheet of
corrugated board 26 having cutouts 28 and 30 to pass through the
spout and handle of the jug. This piece is useful to restrain
rotational movement of the jug during shaking. Finally filler
pieces or pads 32, which may be formed of corrugated board or any
other material, are located on each side of the spout and handle
and preferably bonded to sheet 26. These correspond in thickness to
the height of the spout and handle and bear against the upper flaps
6, 6', 8, 8' when closed. The filler pieces serve to prevent upward
movement of the jug when the package is closed or during agitation
on a shaker.
[0034] Referring now to FIG. 2, assembly steps of the container are
shown. Insert 10 is first placed within the outer box 2 then jug 16
is slid inside the insert. The upper sheet of corrugated board 26
is placed on top of jug 16 then the pads 32 are laid along each
side of the spout 22. Side flaps 6, 6' are first closed to retain
pads 32 the front and rear flaps 8, 8' are closed and glued to
flaps 6, 6' to complete the container 40.
[0035] FIG. 3 shows one of several possible alternative
configurations of the container. Here the separate upper insert 26
and filler pieces 32 shown in FIGS. 1 and 2 are replaced by a piece
generally seen at 42 in which the insert 44 and filler pieces 46
are formed from a single piece of corrugated board. Another
alternative is seen in FIG. 4 in which side flaps 6 of the outer
container 2 are modified and the filler pieces are formed
integrally from extended side flaps 50 by bending along score lines
52.
[0036] Another alternative construction, shown in FIG. 5, would
employ a bladder or jug 50 in which the spout 52 and handle 54, if
present, would be placed below the upper surface of bladder or jug
50. A handle can be conveniently be located within a depressed
portion of the upper surface and a well known telescoping or
popup-type spout used in place of the one shown in the earlier
figures. In this case the filler pieces shown earlier would not
normally be required since the upper surface of the inner plastic
bladder or jug could be flush and in contact with the top flaps 6,
6', 8, 8' of the outer corrugated container. In FIGS. 6 and 7 the
bladder 50 is shown inserted into the corrugated container at 56
and the completed container with the upper flaps sealed at 58.
[0037] Where the container must withstand very severe handling
forces, such as a paint shaker, it is desirable to fill the space
above the rotation prevention sheet 26 and the upper flaps 6, 6',
8, 8' to the maximum extent reasonable. FIG. 8 shows a construction
60 for the filler pieces that serves this purpose. It is also
desirable that the filler pieces, whether of construction 32, 46,
or 60, be relatively rigid so that they do not deform by racking or
in other ways when subject to the forces of a paint shaker.
Preferably, if corrugated paperboard is used, they will have a
minimum of interior void space, other than that within the interior
of corrugations. In addition to the constructions shown, fan-folded
corrugated board, rigid foam materials, honeycomb, wood, etc. are
all suitable. The rotation prevention sheet 26 may also be formed
somewhat differently to assist in reducing tendency of the interior
bladder or jug to rotate during shaking. Rather than the simple
slot 30 seen in the earlier figures, FIG. 9 shows a preferred
construction. The jug or bladder handle 24 is in the form of an
inverted U having upstanding legs and a connecting crosspiece. Two
holes 62, large enough to pass the legs of the handle, are punched
in the sheet. These are connected by a slit 64, embraced by score
lines 66, that permit the handle to be pushed through. After the
handle 24, shown here in phantom view, is inserted the
containerboard on both sides of the slit closes and the two
adjoining sides bear against each other to provide extra
strength.
EXAMPLE 1
[0038] A shipping container approximately 14 inches (35.6 cm) high
and of 10.times.12 inch (25.4.times.30.5 cm) square cross section
was formed from corrugated board having 56 pound liners and 36
pound corrugated medium (274-176-274 kg/m.sup.2). A snugly fitting
insert formed from two pieces of the same board was used to double
the sidewall thickness. A generally rectangular-shaped plastic jug
having an integral handle and spout and having an approximate
10.times.12 inch (25.4.times.30.5 cm) cross section was placed
within the corrugated container. The jug had a wall thickness in
the range of 0.04-0.06 inches (1.0-1.5 mm) with each edge being
rounded on an approximate 3/4 inch (19 mm) radius. Filler pieces
were placed between the upper surface of the jug and the top of the
outer container, the top flaps of the outer container were closed
and sealed, and the jug was then filled with paint. The filled jug
was then placed on a Harbil 5G model paint shaker supplied by Fluid
Management, Inc. Wheeling, Ill. Paint shakers are available from a
number of manufacturers and this should not be considered as an
endorsement of this particular piece of equipment over others that
are available. The shaker has a pair of separated platens that
squeeze together to hold the paint container during shaking. These
platens place a force of about 800-1200 pounds (3600-5400 N) on the
container to hold it in place. The shaker vibrates via a belt
driven offset cam mechanism at about 600 cycles/minute and is
powered by a 3/4 hp (0.56 kW) motor equipped with a current
overload. The shaking time can be adjusted up to a maximum of 3
minutes.
[0039] For this and all subsequent tests the containers were
conditioned to equilibrium at 90% relative humidity prior to
testing. The motor was started with the paint filled container on
the shaker but after about 1 minute the motor overloaded and kicked
out due to overheating. Apparently, sidewall bulging of the
corrugated container had allowed the interior plastic container to
move at a different vibration rate than the shaker. The movement of
the paint-filled plastic interior container evidently began
increasing resistance to the motion of the vibrating platens so
that a motor overload occurred. No leaks were observed in the
plastic inner container. However, agitation time to achieve good
paint mixing was regarded as insufficient.
EXAMPLE 2
[0040] A second container was formed in all ways similar to that of
Example 1 with the exception that the inner liner of the corrugated
container was formed to provide 1 inch (25 mm) corner posts, this
measurement being the length of the truncated corner portions.
Again, the paint shaker motor overloaded and shaking could not
proceed beyond about 1-11/2 minutes. Some wrinkling was noted in
the interior plastic container where it contacted the corner posts.
This wrinkling created stress points that caused pinholes to
develop during shaking and paint leaks to occur.
[0041] A similar container was formed except that the length of the
corner posts was increased from 1 inch to 2 inches (from 2.5 to 5.1
cm). This time the motor did not overload for the full 3 minute
shaking period. However, upon examination, pinhole leaks were again
noted where the corners of the jug had become deformed and wrinkled
from contact with the corner posts in the corrugated container.
Similar results were noted when the corner post length was extended
to 3 inches (7.6 cm).
EXAMPLE 3
[0042] While not in any way limiting of the invention, an outer
container size is 10.times.12 inches (254.times.305 mm) in cross
section and 14 inches (356 mm) high is convenient. This enables 16
containers each holding 5 gallons (18.9 L) or 20 L to be placed on
a standard 40.times.48 inch (1.02.times.1.22 m) Grocery
Manufacturers Association (GMA) pallet. In this example the outer
container was constructed from a corrugated board having a 69 pound
liners and a 36 pound corrugated interior construction (336-176-336
kg/m.sup.2). The secondary sidewall or inner liner was formed in
two pieces and used to provide corner posts having a 1.5 inch (38
mm) length. This was conveniently formed from a corrugated board of
similar weight to the outer box and was spot bonded to the outer
container. It is especially important that the area along the edges
of the corner posts be bonded to the outer container. The inner
liner may be made in either one or two piece construction. While
other constructions of the corrugated components are possible,
those just described use a minimum of fiber to accomplish the
required result. For a box having a major face 12 inches (305 mm)
long, extensive experimentation has shown that the length of the
corner post section of the secondary sidewall should be at least
1.5 inches (38 mm) and preferably less than 3 inches (76 mm). With
a 1.5 inch corner post the ratio of face length to corner post
length is 8:1 for the 12 inch dimension of the outer container and
6.7:1 for the 10 inch dimension. It appears critical that this
ratio should not exceed about 8:1 if sidewall bulging is to be
prevented. For other sizes of outer containers these lengths may be
adjusted somewhat as long as the maximum ratio of length face
length to corner post is not exceeded. It is desirable from the
point of minimizing unused space within the container to reduce
corner post length to the minimum necessary to provide adequate
top-to-bottom stiffness, prevent bulging, and prevent inner
container movement. Shorter corner post lengths; e.g. those greater
than about 8:1 ratio of face to corner post length have been found
to permit considerable movement of the interior container within
the outer container. This usually results in breaker kick-out of
the paint shaker and/or leak formation within the inner plastic
container.
[0043] A new design bladder or jug having an octagonal cross
section was used. The corners were about 2 inches (50.8 mm) wide so
that the jug conformed closely to the interior dimensions of the
corrugated container. This design permits the container filled with
paint and conditioned to equilibrium at 90% relative humidity to
shake a full 3 minutes without motor overload. Movement of the
plastic container within the corrugated container was minimized
during shaking and no wrinkling or pinhole leaks occurred.
[0044] Having described the best mode of construction of the
container, it will be evident to those skilled in the art that
there may be other possible variations in the design that are not
described herein. These should be considered within the purview of
the invention if encompassed within the following claims.
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