U.S. patent application number 10/692583 was filed with the patent office on 2005-04-28 for flexible container.
Invention is credited to LaRoi, John L., Laske, Louis L..
Application Number | 20050089250 10/692583 |
Document ID | / |
Family ID | 34522163 |
Filed Date | 2005-04-28 |
United States Patent
Application |
20050089250 |
Kind Code |
A1 |
Laske, Louis L. ; et
al. |
April 28, 2005 |
Flexible container
Abstract
A flexible container formed by sealing at least two webs of
material with respect to each other to form a void between the
webs. A seal seals a first web with respect to a second web to form
the void. At least one portion of the seal is non-linear,
preferably having an arcuate shape and bowed outward from the void.
The first web defines a closure area which forms an opening to
provide access to the void. A layer of adhesive is applied to the
first web at the closure area to provide for a leak-proof seal at
the closure area when the flexible container is folded with respect
to the void opening.
Inventors: |
Laske, Louis L.;
(Libertyville, IL) ; LaRoi, John L.;
(Libertyville, IL) |
Correspondence
Address: |
PAULEY PETERSEN & ERICKSON
2800 WEST HIGGINS ROAD
SUITE 365
HOFFMAN ESTATES
IL
60195
US
|
Family ID: |
34522163 |
Appl. No.: |
10/692583 |
Filed: |
October 24, 2003 |
Current U.S.
Class: |
383/66 ; 383/107;
383/109; 383/88 |
Current CPC
Class: |
B65D 75/30 20130101 |
Class at
Publication: |
383/066 ;
383/109; 383/107; 383/088 |
International
Class: |
B65D 033/16 |
Claims
What is claimed is:
1. A flexible container comprising: a first web; a second web
positioned with respect to said first web; a seal sealing said
first web with respect to said second web and forming a void
between said webs, at least one portion of said seal being
non-linear; a closure area defined by said first web, said closure
area forming an opening providing access to said void; and a layer
of adhesive applied to said first web at said closure area.
2. The flexible container according to claim 1, wherein said first
web comprises at least two layers.
3. The flexible container according to claim 1, wherein said second
web comprises at least two layers.
4. The flexible container according to claim 1, wherein said seal
is continuous.
5. The flexible container according to claim 1, wherein said at
least one portion of said seal has an arcuate shape.
6. The flexible container according to claim 1, wherein said at
least one portion comprises opposing side edge portions, and in a
direction from a top to a bottom of each of said opposing side edge
portions at least a portion of said side edge portion is bowed
outward from said void.
7. The flexible container according to claim 1, wherein a bottom
portion of said seal is bowed outward from said void.
8. The flexible container according to claim 7, wherein said bottom
portion follows an arc segment and a height of said arc segment is
at least about 0.125 inch.
9. The flexible container according to claim 1, wherein opposing
side edge portions of said seal converge in a direction toward a
bottom portion of said seal.
10. The flexible container according to claim 1, wherein opposing
side edge portions of said seal each is arcuate.
11. The flexible container according to claim 1, wherein opposing
side edge portions of said seal each is bowed outward from said
void and follows an arc segment and a height of said arc segment is
at least about 0.125 inch.
12. The flexible container according to claim 1, wherein a portion
of each of opposing side edge portions of said seal is arcuate.
13. The flexible container according to claim 1, wherein near said
closure area, opposing side edge portions of said seal diverge from
each other in a direction from a bottom to a top of said side edge
portions.
14. The flexible container according to claim 1, wherein said first
web has at least two layers and a first layer of said at least two
layers is coextensive with a second layer of said at least two
layers.
15. The flexible container according to claim 1, wherein said first
web has at least two layers and said at least two layers comprise a
first layer of a polyester or nylon material and a second layer of
a polyethylene material.
16. The flexible container according to claim 1, wherein said
opening comprises a slit positioned along a fold line passing
through said closure area.
17. The flexible container according to claim 16, wherein near at
least one of opposing end portions of said slit at least one of
said webs has a structural relief.
18. The flexible container according to claim 17, wherein said
structural relief comprises at least one layer of at least one of
said webs having a reduced thickness at said fold line.
19. A flexible container comprising: a first web and a second web
sealed with respect to each other and forming a void between said
webs, said first web having an opening at a closure area, and a
seal sealing said webs, said seal having a bottom portion and
opposing side edge portions each being non-linear.
20. The flexible container according to claim 19, wherein each of
said first web and said second web comprises at least two
layers.
21. The flexible container according to claim 19, wherein said seal
comprises a continuous seal.
22. The flexible container according to claim 19, wherein each of
said bottom portion and said opposing side edge portions has an
arcuate shape.
23. The flexible container according to claim 22, wherein said
bottom portion has a radius of about 8 inches.
24. The flexible container according to claim 22, wherein each of
said opposing side edge portions has a radius of about 70
inches.
25. The flexible container according to claim 19, wherein each of
said bottom portion and opposing side edge portions is bowed
outward from said void.
26. The flexible container according to claim 25, wherein said
bottom portion follows an arc segment and a height of said arc
segment is at least about 0.125 inch.
27. The flexible container according to claim 25, wherein each of
opposing side edge portions follows an arc segment and a height of
said arc segment is at least about 0.125 inch.
28. The flexible container according to claim 19, wherein a top
portion of said seal is non-linear.
29. The flexible container according to claim 19, wherein a top
portion of said seal is arcuate.
30. The flexible container according to claim 19, wherein said side
edge portions converge in a direction toward said bottom
portion.
31. A flexible container comprising: a first web; a second web
sealed with respect to said first web and forming a void between
said webs; a closure area defined by said first web, said closure
area forming an opening providing access to said void; a seal
sealing said first web with respect to said second web to form said
void, a bottom portion of said seal being non-linear, and near said
closure area, opposing side edge portions of said seal diverge from
each other in a direction from a bottom to a top of said side edge
portions; and a layer of adhesive applied to said first web at said
closure area.
32. The flexible container according to claim 31, wherein said seal
is continuous.
33. The flexible container according to claim 31, wherein said
bottom portion has an arcuate shape.
34. The flexible container according to claim 31, wherein said
opposing side edge portions converge in a direction toward said
bottom portion.
35. The flexible container according to claim 31, wherein a top
portion of said seal is non-linear.
36. The flexible container according to claim 31, wherein a top
portion of said seal is arcuate.
37. The flexible container according to claim 31, wherein said seal
comprises a heat seal.
38. The flexible container according to claim 31, wherein said seal
is formed about a periphery of the flexible container.
39. The flexible container according to claim 31, further
comprising a second seal positioned with respect to said void.
40. The flexible container according to claim 39, wherein said
second seal is segmented.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a flexible container, particularly
a flexible container having a seal with non-linear seal portions,
wherein forces exerted on the seal by fluid materials contained
within the flexible container are more evenly distributed along the
seal, and forming an extended opening for easy access to a void
without increasing the overall width of the flexible container.
[0003] 2. Description of Related Art
[0004] Under new Federal Aviation Administration (FAA), in the
United States, testing criteria in the United States, a container
must be able to withstand a sustained internal pressure of about 14
psi for at least about 30 minutes in order to be suitable for
transporting toxic and other hazardous materials, using air
transportation. For example, if an airplane traveling at an
elevation of about 42,000 feet is depressurized, the container must
withstand a net effect of an internal pressure of about 14 psi in
order to remain sealed. Many conventional containers, particularly
flexible containers, cannot withstand such high internal pressure.
As a result, a conventional flexible container leaks through a
closure which sealably closes a container opening, breaks at a weak
peripheral seal or deforms or expands at a region and develops an
opening, whereby the materials contained within the container leak
from the container.
[0005] For example, it is very difficult to provide a flexible
container that can withstand high internal pressures and maintain a
leak-proof closure. Conventional flexible containers typically have
a general rectangular void area when in a flat or uninflated
condition. The seal which forms the void is positioned about a
periphery of the flexible container and includes a bottom portion,
a top portion and opposing side edge portions. The seal portions
are generally linear or straight. As a result, when the flexible
container is inflated or filled with a fluid material and subjected
to increased internal pressure, forces exerted on the side walls
and the seal cause a center of the seal portions to be pulled
inward toward the void, thus causing the seals to form an
hour-glass shaped void. This causes even greater forces to be
exerted on the seal which may result in failure of the seal at a
weak portion of the seal or closure area and leakage of the
material contained within the flexible container, particularly when
the flexible container is subjected to a high internal
pressure.
[0006] There is an apparent need for a flexible container wherein
forces exerted by the material contained within the flexible
container on the seal are reduced and/or more evenly distributed
along the seal.
[0007] There is also an apparent need for a flexible container
wherein portions of the seal are generally linear when filled with
a fluid material.
[0008] There is also an apparent need for a flexible container
which provides an increased opening for placing material within the
flexible container without increasing the overall width of the
flexible container.
SUMMARY OF THE INVENTION
[0009] It is an object of this invention to provide a flexible
container having a seal with non-linear seal portions when in a
flat or uninflated condition, to more evenly distribute forces
exerted on the seal when fluid materials are contained within the
flexible container.
[0010] It is another object of this invention to provide a flexible
container that provides an increased opening to provide access to
the void formed by the flexible container while providing seal
portions which distribute forces more evenly along the seal.
[0011] The above and other objects of this invention are
accomplished with a flexible container having at least two webs
positioned and sealed with respect to each other about a periphery
of the flexible container, to form a void between the webs. In one
preferred embodiment of this invention, the first web and/or the
second web includes two or more layers of material. For example,
the first web may include a first or outer layer made of a polymer
material, such as a polyester or nylon or other similar material,
and a second or inner sealant layer made of a polymer material,
such as a polyethylene material. Similarly, the second web may
include a first layer and a second layer. Preferably, but not
necessarily, the first layer of the second web includes a material
the same or similar to the first layer of the first web and the
second layer comprises a material the same or similar to the second
layer of the first web. Alternatively, the first layer and the
second layer of the second web may include a different material
than the first layer and the second layer of the first web,
respectively.
[0012] At least one seal joins or seals the first web with respect
to the second web and forms the void between the webs. The seal is
preferably formed about a periphery of the flexible container using
any suitable sealing process, for example a heat sealing process
and/or an adhesive sealing process. It should be apparent to those
skilled in the art that other suitable sealing processes may be
used to form the seal. Additional seals may be formed and
positioned with respect to the void. For example, a second seal,
continuous or segmented, can be formed within the primary seal to
maintain the void in a proper configuration or shape.
[0013] Preferably, at least one seal is continuous and at least an
inner edge of at least one portion of the seal is non-linear. In
one embodiment of this invention, an inner edge of at least one
portion of the seal has an arcuate shape. For example, an inner
edge of at least one of a bottom portion, a top portion and/or
opposing side edge portions of the seal has an arcuate shape.
Preferably, the arcuate-shaped inner edge of the portion or
portions of the seal are bowed outward from the void.
[0014] In one preferred embodiment of this invention, the inner
edge of the bottom portion of the seal is bowed outward from the
void. Preferably, the inner edge of the bottom portion follows an
arc segment wherein a height of the arc segment, as defined below,
is at least about 0.125 inch. Additionally or alternatively, at
least a portion of the inner edge of at least one opposing side
edge portion is bowed outward from the void, in a direction from a
top to a bottom of the respective opposing side edge portion.
Similarly, the non-linear or arcuate inner edge of opposing side
edge portions of the seal follow an arc segment wherein a height of
the arc segment is at least about 0.125 inch. In one preferred
embodiment of this invention, the opposing side edge portions
converge in a direction toward the bottom portion of the seal.
Additionally, near a closure area formed or defined by the flexible
container, at least the inner edge of the opposing side edge
portions of the seal may diverge from each other in a direction
from the bottom to the top of the side edge portions to provide a
large or extended opening in the closure area. An inner edge of the
top portion of the seal may also be non-linear, for example
arcuate. The inner edge of the top portion may be bowed outward
from the void. Preferably, the inner edge of the top portion
follows an arc segment wherein a height of the arc segment is at
least about 0.125 inch.
[0015] The flexible container also includes a closure area defined
by the first web. The closure area forms an opening which provides
access to the void. In one preferred embodiment of this invention,
the opening includes a slit positioned along a fold line that
passes through the closure area. Preferably, but not necessarily,
at least one of the first web and the second web has a structural
relief near at least one of opposing end portions of the slit. The
structural relief includes at least one layer of at least one of
the first web and the second web having a reduced thickness at the
fold line. A layer of adhesive is applied to the first web at the
closure area to provide a tight leak-proof seal about the opening
when a top portion of the flexible container is folded along the
fold line with respect to a bottom portion of the flexible
container and about the opening.
[0016] Other objects and advantages of this invention will be
apparent to those skilled in the art from the following detailed
description taken in conjunction with the appended claims and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The drawings show different features of a flexible
container, according to preferred embodiments of this invention,
wherein:
[0018] FIG. 1 is a front view of a flexible container in a flat or
unfolded condition, according to one preferred embodiment of this
invention;
[0019] FIG. 2 is a cross-sectional side view of the flexible
container taken along sectional line A-A as shown in FIG. 1;
[0020] FIG. 3 is a front view of a flexible container in a flat or
unfolded condition, according to another preferred embodiment of
this invention;
[0021] FIG. 4 is a front view of a flexible container in a flat or
unfolded condition, according to another preferred embodiment of
this invention;
[0022] FIG. 5 is a front view of a flexible container in a flat and
unfolded condition, showing an arc segment of an arcuate seal
portion, according to another preferred embodiment of this
invention;
[0023] FIG. 6 is a front view of a flexible container in a flat or
unfolded condition, according to another preferred embodiment of
this invention;
[0024] FIG. 7 is a front view of a flexible container having a seal
forming a generally circular void, in a flat or empty
condition;
[0025] FIG. 8 is a front view of a flexible container having a seal
forming a generally circular void, and showing forces exerted on
the seal when the flexible container is filled with a fluid
material and subjected to an increased internal pressure;
[0026] FIG. 9 is a side view of a flexible container having a seal
forming a generally circular void, in a flat or empty
condition;
[0027] FIG. 10 is a side view of a flexible container having a seal
forming a generally circular void, filled with a fluid material and
subjected to an increased internal pressure;
[0028] FIG. 11 is a front view of a conventional flexible container
having a seal forming a generally rectangular void, in a flat or
empty condition;
[0029] FIG. 12 is a front view of a conventional flexible container
having a seal forming a generally rectangular void, and showing
forces exerted on the seal when the conventional flexible container
is filled with a fluid material and subjected to an increased
internal pressure;
[0030] FIG. 13 is a side view of a conventional flexible container
having a seal forming a generally rectangular void, in a flat or
empty condition; and
[0031] FIG. 14 is a side view of a conventional flexible container
having a seal forming a generally rectangular void, filled with a
fluid material and subjected to an increased internal pressure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] Referring to FIGS. 1-6, a flexible container 10 comprises a
first web of material 20 and a second web of material 40, one on
each side of flexible container 10, joined and/or sealed with
respect to each other to form a void 28 between webs 20, 40. In
other preferred embodiments of this invention, each web 20, 40 may
comprise more than one layer of material and either side of
flexible container 10 can include two or more webs 20, 40.
[0033] The term "flexible" refers to the ability of flexible
container 10 to bend, stretch, expand or contract, for example,
without permanent deformation or failure, to adapt to changing
environments, for example a change in pressure or change in
temperature. It is apparent that flexible container 10 and/or void
28 formed between webs 20, 40 can have any suitable shape and/or
dimensions which allows flexible container 10 to function properly
for a particular purpose. Flexible container 10 may comprise at
least one component or element similar to a corresponding component
or element as taught in U.S. Pat. No. 5,336,123 issued to Laske et
al. on Aug. 9, 1994 and/or as taught in copending, commonly owned
U.S. patent application Ser. No. 10/165,633, filed on 7 Jun. 2002
naming Louis L. Laske as the inventor, the disclosures of which are
incorporated by reference into this specification.
[0034] Throughout this specification, as discussed above, one side
of flexible container 10 may include one or more first webs 20 and
the opposing side of flexible container 10 may comprise one or more
second webs 40. As different elements and features are discussed
throughout this specification, when referring to one first web 20
and/or one second web 40, such discussion can be interchanged with
discussion related to either side of flexible 10 having two or more
first webs 20 and/or two or more second webs 40.
[0035] In one preferred embodiment of this invention, each web 20,
40 has a total thickness of about 0.003 inch to about 0.010 inch
and comprises at least two layers of material that are coextensive.
The term "coextensive" as used throughout this specification and in
the claims refers to the positioning of web 20 with respect to web
40, wherein web 20 is aligned with web 40 such that web 20 and web
40 generally have the same or similar outer boundaries, for example
boundaries forming the edges of flexible container 10. In one
preferred embodiment of this invention, first web 20 includes a
first or outer layer made of a polymer material, such as a
polyester or nylon or other similar material, having a thickness of
about 0.00025 inch to about 0.0015 inch and a second or inner
sealant layer made of a polymer material having a thickness of
about 0.0005 inch to about 0.006 inch. The first layer may comprise
a 0.00060 inch, for example, biaxial oriented nylon material, such
as available from Clear-Lam, located in Illinois, United States.
The biaxial oriented nylon material provides a strong structure due
to equal or similar tensile strengths in the longitudinal direction
and the lateral direction of the material. Preferably, the second
layer comprises a 0.0015 inch polyethylene material, such as
available from Southern Films located in Florida, U.S.A., a
material which is known as a linear low density polyethylene. Other
suitable materials known to those skilled in the art may be used to
make the first layer and/or the second layer of first web 20 and/or
second web 40.
[0036] Similarly, second web 40 may include a first layer and a
second layer. Preferably but not necessarily, the first layer
comprises a material the same or similar to the first layer of
first web 20 and the second layer comprises a material the same or
similar to the second layer of first web 20. Alternatively, the
first layer and the second layer may comprise a different material
than the first layer and the second layer of first web 20,
respectively. In one preferred embodiment of this invention, first
web 20 and second web 40 each comprises a third layer sealed with
respect to the first and second layers. For example, a third layer
(not shown) made of 0.0015 inch polyethylene, for example, may be
sealed with respect to the first layer to sandwich or position the
first layer between the second layer and the third layer.
[0037] The first layers and the second layers, and any additional
layers, may be made of any suitable compatible materials, for
example polymer materials, which when combined to form one or more
of each of webs 20, 40 exhibit a combined strength capable of
withstanding a wide pressure and/or temperature range. The multiple
layer, multiple web construction of flexible container 10 provides
a strong structure because one layer supports the other layer.
Preferably, flexible container 10 is capable of withstanding a
constant or sustained internal pressure of at least about 14 psi.
The closure at closure area 62 and the corresponding material of
the closure can withstand temperatures of about -40.degree. F. to
about 130.degree. F., without deformation of and/or leakage through
the closure.
[0038] Preferably, first web 20 and second web 40 are heat sealed
to form a seal 30 about a periphery of flexible container 10, as
shown in FIGS. 1, 3 and 4. Any other suitable process for sealing,
as known to those skilled in the art, can be used to form one or
more seals between webs 20, 40. In one preferred embodiment of this
invention, seal 30 preferably has a width of at least about 0.125
inch, and more preferably at least about 0.375 inch, but in other
embodiments can be larger or smaller depending upon the overall
size of flexible container 10 and the material which flexible
container 10 may contain. In another preferred embodiment of this
invention, seal 30 can have a variable width and/or any other shape
at any point or in any direction about the periphery of seal 30. It
is apparent that other suitable bonding means, for example
adhesives and the like, may be used to form seal 30 and attach or
bond webs 20, 40. Flexible container 10 may comprise additional
seals, as required. For example, if the side of flexible container
10 that has opening 60 has two or more first webs 20, then a seal
31 such as shown in FIG. 1 can be used to heat seal the two or more
first webs 20 together, wherein seal 31 surrounds or is below
opening 60, as shown in FIG. 1. In another preferred embodiment of
this invention, a seal 32 extends along at least a portion at or
near a top edge and/or a bottom edge of flexible container 10 to
seal first web 20 to second web 40.
[0039] Referring to FIGS. 1-6, second web 40 is positioned with
respect to first web 20 and webs 20, 40 are sealed to form void 28
between webs 20, 40. As discussed above, it is apparent that webs
20, 40 can be sealed using any suitable sealing process, such as a
heat sealing process and/or an adhesive sealing process.
Preferably, seal 30 is continuous and is formed about a periphery
of flexible container 10. Void 28 formed between webs 20, 40 can
have any suitable shape and/or dimensions which allows flexible
container 10 to function properly for a particular purpose.
[0040] Preferably, at least an inner edge of at least one portion
of seal 30 is non-linear. For example, referring to FIGS. 1, 3 and
4, an inner edge of at least one portion of seal 30 has an arcuate
shape. As shown in FIG. 1, an inner edge of a bottom portion 33, a
first side edge portion 34 and/or a second side edge portion 35,
opposing first side edge portion, has an arcuate shape. Further, at
least an inner edge of a top portion 36 of seal 30 may be arcuate
or otherwise non-linear. It is critical to the present invention
that at least the inner edge of seal portion 33, 34, 35 and/or 36
is non-linear, for example having an arcuate shape. Seal 30,
including an outer edge of seal portions 33, 34, 35 and 36, can
have any suitable shape or configuration. For example, as shown in
FIG. 1, an inner edge of each of seal portions 33, 34, 35 has an
arcuate shape, while an outer edge of seal portion 33, 34 and 35 is
generally linear.
[0041] Referring to FIGS. 7-10, seal portions having an inner edge
with an arcuate shape in a flat or uninflated condition can better
distribute pressure within void 28 because as a seal approaches a
generally circular shape, forces exerted against the seal by
materials contained within void 28 will be more evenly distributed
about the seal. As shown in FIGS. 7-10, a flexible container 100
having a seal 110 forming a void 120 having a generally circular
shape can better distribute pressure within void 120 and against
seal 110, when compared to a conventional flexible container 200
having a seal 210 forming a void 220 having a generally rectangular
shape, as discussed above and shown in FIGS. 11-14. Thus, the
resultant stresses on seal 110 at all points about the seal
periphery should be generally equal, and circular void 120 should
remain circular, when filled with a fluid material and subjected to
an increased internal pressure, as shown in FIG. 8. Conversely, as
shown in FIG. 12, when conventional flexible container 200 having
rectangular shaped void 220 is filled with a fluid material and
subjected to an increased internal pressure, center portions of
seal 210 are pulled inward toward void 220, thus causing seal 210
to form an hour-glass shaped void. Such deformation can result in
seal failure and leakage of the material contained within void
220.
[0042] Preferably, but not necessarily, each arcuate-shaped portion
of seal 30 is bowed outward from void 28. Referring to FIGS. 1 and
5, the inner edge of bottom portion 33 of seal 30 is bowed outward
from void 28. As shown in FIGS. 1 and 3-6, the inner edge of bottom
portion 33 follows an arc segment and a height of the arc segment
is at least about 0.125 inch. The term "arc segment" as used
throughout this specification and in the claims refers to a curved
or arcuate portion of seal 30. Referring further to FIG. 5, an arc
segment s has a length determined between two points of
intersection between a chord c and an inner edge of arcuate-shaped
seal portion 33. The height h of arc segment s can be defined as
the difference between a radius r of a circle including arc segment
s and a distance d from a center of the circle to a point, such as
the midpoint, of chord c, as shown in FIG. 5. Similarly, inner
edges of each side edge portion 34, 35 can also be bowed outward
from void 28, as shown in FIG. 1. Preferably, at least a portion of
the inner edge of side edge portion 34 and/or 35 is bowed outward
from void 28 in a direction from a top to a bottom of side edge
portion 34 and/or 35. Preferably, but not necessarily, the inner
edge of opposing side edge portions 34, 35 of seal 30 each is bowed
outward from void 28 and follows an arc segment having a height of
at least about 0.125 inch. In other embodiments, one or more of
seal portions 33, 34, 35 and/or 36 can have any suitable non-linear
shape or configuration.
[0043] Referring to FIGS. 1 and 5, for one embodiment of a flexible
container 10 having a width (from side edge to side edge) of about
6.875 inches and a length (from top to bottom) of about 11.875
inches, the radius r of bottom portion 33 is preferably about 8
inches in order to form bottom portion 33, having an inner edge
which bows outward from void 28 by about 0.125 inch. Further, the
radius r of each of opposing side edge portions 34, 35 is
preferably about 70 inches in order to form side edge portions 34
and/or 35, having inner edges which bow outward from void 28 by
about 0.125 inch.
[0044] As shown in FIG. 3, in one preferred embodiment of this
invention, the inner edge of bottom portion 33 of seal 30 has an
arcuate shape and opposing side edge portions 34, 35 of seal 30
converge in a direction toward bottom portion 33. Opposing side
edge portions 34, 35 can be generally linear, as shown in FIG. 3,
or at least a portion of the inner edge of opposing side edge
portions 34 and/or 35 can be generally non-linear, for example
having an arcuate shape, as shown in FIGS. 1 and 4.
[0045] Referring further to FIG. 4, in one preferred embodiment of
this invention, side edge portion 34 and/or 35 can include a
non-linear portion, for example having a curved or arcuate shape,
as well as a linear portion. As shown in FIG. 4 for example, near
closure area 62, the inner edge of opposing side edge portions 34,
35 of seal 30 diverge from each other in a direction from a bottom
37 to a top 38 of side edge portions 34, 35 in order to maximize
the length of opening 60. The inner edge of opposing side edge
portions 34, 35 may also include a portion which is generally
linear and/or parallel to a respective side edge of flexible
container 10, as shown in FIG. 4, or opposing side edge portions
34, 35 may converge in a direction toward bottom portion 33,
similar to the preferred embodiment shown in FIG. 3. In the
preferred embodiments as shown in FIGS. 3 and 4, flexible container
10 includes an extended or large opening 60 which provides easy
access to void 28.
[0046] In one embodiment of this invention, flexible container 10
further comprises a second seal 39 positioned inward with respect
to void 28, as shown in FIG. 6. Second seal 39 can be a continuous
seal about at a least a portion of the periphery of flexible
container 10 or can be segmented or noncontinuous, as shown in FIG.
6. Preferably, at least a portion of second seal 39 is non-linear,
such as having an arcuate shape. As shown in FIG. 6, second seal 39
is bowed outward from void 28. Alternatively, second seal 39 can be
generally linear and/or parallel to a respective side edge of
flexible container 10. Segmented second seal 39 allows fluid
materials contained within void 28 to move, flow or communicate
beyond a sealing line of second seal 39 towards seal 30 formed
about the flexible container periphery, while maintaining a desired
void shape or configuration to distribute forces evenly along or
against seal 30.
[0047] Referring to FIGS. 1, 3 and 4, first web 20 forms an opening
60 at or within a closure area 62 defined by first web 20 to
provide access to void 28. Preferably, but not necessarily, opening
60 comprises a slit which is positioned along, at or near a fold
line 99, which passes through closure area 62, as shown in FIG. 1.
Opening 60 may extend outward in a direction toward seal 30 any
suitable distance. Opening 60 may stop short of seal 30, may extend
up to an inner edge of seal 30, may extend into seal 30, may extend
up to an outer edge of seal 30, and/or may extend beyond seal 30
into a skirt 75. To whatever distance opening 60 extends, there
should be a sufficient area of adhesive contact, either
adhesive-to-adhesive or adhesive to web 20, to ensure a tight seal
at or near end portions 71, 73 of opening 60 to provide a tight
leak-proof seal about opening 60, particularly when flexible
container 10 is folded about fold line 99. Further, as a distance
between end portion 71 and/or 73 and seal 30 decrease, a width of
seal 30 and/or a width of skirt 75 defined by a portion of flexible
container 10 between edges 13, 15 of flexible container 10,
respectively, and an outer edge of seal 30 preferably but not
necessarily increases.
[0048] An adhesive layer 68 is applied to at least a portion of
first web 20 at closure area 62. Any suitable adhesive known to
those skilled in the art can be used to form adhesive layer 68,
which provides a sufficiently strong adhesive seal to close opening
60. A cover strip 50 can be applied to or positioned on adhesive
layer 68, such that adhesive layer 68 is sandwiched or positioned
between first web 20 at closure area 62 and cover strip 50.
Preferably, cover strip 50 and adhesive layer 68 form a pressure
sensitive tape material, as is well known in the art. The pressure
sensitive material can be applied as a preformed material or can be
applied in manufacturing steps as adhesive layer 68 and cover strip
50.
[0049] In one preferred embodiment of this invention, at least one
web 20, 40 has at least one structural relief 69. As shown in FIG.
1, structural relief 69 is formed by notched areas 70 positioned at
or near end portion 71 and/or 73 of opening 60. The term
"structural relief" as used throughout this specification and in
the claims refers to any structural feature or material property of
any one or more layers of web 20, 40 that decreases a magnitude of
the shape memory or bias force of web 20, 40. Shape memory relates
to a folded web 20, 40 that urges itself back to an unfolded
position or state, and is one problem associated with conventional
flexible containers, and is directly related to container
leakage.
[0050] In one preferred embodiment of this invention, structural
relief 69 comprises a notched area 70 formed in one or more layers
of web 20 and/or one or more layers of web 40 and extending a
distance on one or both sides of fold line 99, as shown in FIG. 1.
Notched area 70 may be formed by removing or otherwise eliminating
at least one layer of first web 20 and/or second web 40 at notched
area 70. Preferably, first web 20 and/or second web 40 comprises
notched area 70 at or near one or both side edges 13, 15 of
flexible container 10. Notched area 70 extends at least partially
between outer edge 13, 15 of flexible container 10 and respective
end portion 73, 71 of opening 60. Depending on the number of layers
in each web 20, 40, notched area 70 can extend inward further than
end portion 71 and/or 73. Further, notched area 70 may extend
through only one layer or more than one layer of first web 20
and/or second web 40, and may extend laterally into a corresponding
portion of seal 30.
[0051] Referring to FIGS. 1 and 2, when adhesively sealing opening
60 of flexible container 10 at closure area 62, cover strip 50 is
removed, for example by peeling cover strip 50 from adhesive layer
68. A top portion 12 of flexible container 10, above fold line 99,
is folded to contact a bottom portion 14 of flexible container 10,
below fold line 99. Preferably, to provide a tight leak-proof seal,
flexible container 10 is folded along fold line 99. Adhesive layer
68 provides a leak-proof seal about opening 60 in closure area 62.
In one preferred embodiment of this invention, adhesive layer 68 is
positioned on top portion 12 and extends towards fold line 99 to a
bottom edge 101 of adhesive layer 68, as shown in FIG. 6. When top
portion 12 is folded at fold line 99 with respect to bottom portion
14, the adhesive on top portion 12 contacts an outer surface of
first web 20 on bottom portion 14 to form an adhesive-to-layer
bond. Depending on the design parameters and/or the intended use
for flexible container 10, adhesive layer 68 can extend from top
portion 12 any suitable distance toward fold line 99 and terminate
either before, at or beyond fold line 99, preferably but not
necessarily so that when folded, adhesive layer 68 fully surrounds
opening 60 to completely seal opening 60. In one preferred
embodiment of this invention as shown in FIG. 1, at least one
structural relief 69, for example notched area 70 is formed in
first web 20 and/or second web 40 by preferably, but not
necessarily, removing or otherwise eliminating, such as through a
manufacturing process, a portion of at least one layer of first web
20 and/or at least one layer of web 40. Preferably, fold line 99
passes through notched area 70. Fold line 99 defines the
longitudinal position of opening 60 with respect to flexible
container 10.
[0052] In one embodiment of this invention, when flexible container
10 is folded about fold line 99, adhesive layer 68 folds over onto
itself to form an adhesive-to-adhesive bond and/or folds over onto
an outer surface of first web 20 to form an adhesive-to-layer bond.
In either case, because of the shape memory or bias force within
the layer at fold line 99 the layer has a tendency to unfold or
open flat. By applying more pressure to the layer at fold line 99,
the adhesive-to-adhesive and/or the adhesive-to-layer bond strength
is increased. Providing one or more notched areas 70 at fold line
99 allows more direct pressure applied at fold line 99 which
enhances the bond strength provided by adhesive layer 68 and
reduces the shape memory as well.
[0053] While in the foregoing specification the invention has been
described in relation to certain preferred embodiments, and many
details are set forth for purpose of illustration, it will be
apparent to those skilled in the art that the invention is
susceptible to additional embodiments and that certain of the
details described in the specification and in the claims can be
varied considerably without departing from the basic principles of
the invention.
* * * * *